Title of Invention	"APPARATUS FOR PRODUCTION OF METAL MATRIX COMPOSITE BILLETS REINFORCED WITH SILICON CARBIDE AND PROCESS THEREOF"
Abstract	This invention relates to an apparatus for production of metal matrix composite billets, reinforced with silicon carbide particularly for explosive compaction of a metal such as 2124 Aluminium alloy, reinforced with silicon carbide comprising of particulate (SiC) to produce metal matrix composite billets, comprising a collapsible outer container (1) with lids (8) and (9) to close its two ends, characterized in that is; an inner metallic container (2) with lids (4) and (5) to close its two ends an explosive powder is packed in the annular space between inner metallic container (2) and outer container (1); a wooden cone (6); an electric detonator (10) to initate producing convergent cylindrical shock waive.

Title of Invention

"APPARATUS FOR PRODUCTION OF METAL MATRIX COMPOSITE BILLETS REINFORCED WITH SILICON CARBIDE AND PROCESS THEREOF"

Abstract

This invention relates to an apparatus for production of metal matrix composite billets, reinforced with silicon carbide particularly for explosive compaction of a metal such as 2124 Aluminium alloy, reinforced with silicon carbide comprising of particulate (SiC) to produce metal matrix composite billets, comprising a collapsible outer container (1) with lids (8) and (9) to close its two ends, characterized in that is; an inner metallic container (2) with lids (4) and (5) to close its two ends an explosive powder is packed in the annular space between inner metallic container (2) and outer container (1); a wooden cone (6); an electric detonator (10) to initate producing convergent cylindrical shock waive.

Full Text	FILED OF INVENTION This invention relates to process and apparatus for production of metal matrix composite billets reinforced with silicon carbide (SiCp) particulate, through explosive compaction. Though the present invention is described in relation to explosive compaction process for 2124 aluminium alloy reinforced with silicon carbide (SiCp) particulate to produce metal matrix composite billets, however, it is not intended to imply any limitation as the apparatus and process of the present invention can be used for alloys of other metals and also for other grades of aluminium besides the grade 2124 of aluminium described in the present invention. PRIOR ART Silicon carbide particulate reinforced aluminium metal matrix composites have higher stiffness and resistance to fatigue, creep and wear compared to many wrought aluminium alloys. These materials are receiving & great deal of attention for demanding applications in aerospace, electronic packaging and automobile industries. Conventional powder metallurgy process for production of 2124 Al alloy-with upto 30 vol.% SiCp) metal matrix composite billets involves cold compaction followed by hot pressing which are cumbersome and experts be. The above conventional process has the disadvantage that it involves high capital investments in equipment. Another disadvantage of above process is that it involves undesirable long processing time. Still another disadvantage of the above process is that it requires prolonged exposure to high temperature which in turn has the disadvantage that it shortens the life of the composites. Further disadvantage of the above process is that the prolonged exposure to high temperature, required in these processes, leads to the formation of coarse intermetal1ic compounds which adversely affect the properties of the composites billets. Yet further disadvantage of the above process is that it degrades the microstructure of 2124 Al alloy powders. OBJECTS OF PRESENT INVENTION The primary object of the present invention is to provide an explosive compaction process and an apparatus thereof, for producing metal matrix composite billets of metals in general, particularly for explosive compaction of 2124 Al alloy reinforced with silicon carbide (SiCp) particulate to produce metal matrix composite billets. Another object of the present invention is to propose a process and an apparatus which produces metal matrix composite billets of 2124 Al with SiCp which have density comparable to that obtained by conventional hot pressing. Still another object of the present invention is to provide a single stage process for composite powder compaction, to produce metal matrix billets, directly from the raw material, thereby eliminating the need for secondary forming operations like forging and extrusion. Further object of the present invention is to propose a process and an apparatus which provides a significantly economical process for producing metal matrix composite billets of 2124 Al with SiCp as it avoids the requirement of large presses and extrusion machinery. Still further objects of the present invention is to propose a process and an apparatus which produces metal matrix composite billets of 21 24 Al with SiCp in comparatively less time as compared to the conventional process. Yet further objects of the present invention is to propose a process and an apparatus which produces metal matrix composite billets of 2 124 Al with SiCp, wherein the original powder microstructure is retained even after the compaction process is completed. STATEMENT OF INVENTION According to this invention there is provided a process and apparatus for production of metal matrix composite billets, reinforced with silicon carbide, particularly for explosive compaction of a metal such as 2124 Aluminium alloy, reinforced with silicon carbide comprising of particulate (SiCp) to produce metal matrix composite billets, comprising: a) a collapsible outer container with lids and to close its two ends, characterized in that is; of an inner metallic container with lids and 10 close its two ends; c) an explosive powder is packed in the annular space between inner metallic container and outer container; d) a wooden cone; e) an electric detonator to initate producing convergent cylindrical shock waive. Further according to this invention there is provided A process for producing reinforced metal matrix composite billets using the apparatus as claimed in claim 1 which comprises in the steps of: a) packing composite powder mix in a metallic container closed from both ends by metal plugs and and placing a cone over upper end; b) placing centrally the metal container inside an outer container covered with the lids from both the ends; c) filling the annular space between metal container and container with explosive mixture; d) detonating the explosive which compacts the composite powder placed in metallic container by the convergent cylindrical shock waves thus produced and which collapses the container. The present invention provides a process and an apparatus by which reinforced metal matrix composites like metal matrix composites of 2124 Aluminium alloy reinforced with upto 30 vol% of silicon carbide paniculate can be compacted through explosive compaction to produce metal matrix composite billets. The invention uses energy of shock waves generated through detonating an explosive powder to compact the composite powder to produce metal matrix composites. The apparatus involves two coaxial cylinders with inner cylinder as metallic cylinder,; preferably aluminium cylinder and the outer cylinder , made of plastic. The inner cylinder is packed with composite powder to be explosive-compacted while annular space between the two cylinders is filled with required explosive composition A wooden cone on the top of the inner cylinder enables modification of shock front. The explosive powder- is detonated with an " electrical detonator provided at the top of apparatus. The metal matrix composite produced by explosive compaction through the apparatus of the present invention is significantly economical as it avoids the use of expensive large presses. The explosive compaction through the apparatus of the present invention enables the production of metal matrix composites directly from raw material thereby eliminating secondary forming operations like forging and extrusion. The density of metal matrix composites produced through the apparatus of the present invention is comparable to the metal matrix composites produced through the conventional hot pressing and extrusion. The explosive compaction through the apparatus of the present invention also takes less lime as compared to processes known in the art and also results in the microstructure having original dendritic structure of the matrix metal with a uniform distribution of reinforcement particles all around the matrix metal particles. PRESCRIPTION OF FIGURES The objects of the present invention will be more clearly understood from the following detailed description in conjunction with the accompanying drawings which show an illustrative embodiment of the apparatus which is not intended to imply any limitation, in any way, on the scope of the present invention. In the accompanying drawings of the apparatus for carrying out explosion process, the different figures depict as follows:- Figure 1: shows the complete assembly of the apparatus Figure 2(a) shows front view of metallic (aluminium) container; Figure 2(b) shows top view of metallic container; Figure 2(c) & 2(d) shows front view of the two metallic plugs used to close the metallic container from bottom-end and upper-end. Figure 2(e) shows top view of the two metallic plugs; Figure 2(f) shows the front view of the wooden cone; Figure 2(g) shows the bottom view of the wooden cone Figure 2(h) shows front view of the outer plastic container; Figure 2(i) shows top view of the outer plastic container; Figure 2(k) & 2(1) shows front view of top plastic cover plates for closing the two ends of plastic container; Figure 2(m) shows top view of plastic cover plates for closing the two ends of plastic container; Figure 2(n) shows the electric detonator. DESCRIPTION OF THE APPARATUS WITH REFERENCE TO DRAWINGS The process of the present invention will now be described with respect to the accompanying figures. Referring to Fig 1, the apparatus for producing metal matrix composite billets comprises of cylindrical metal container (2), preferably aluminium container having preferably about 26 mm internal diameter with 3 to 5 mm wall thickness. One end of the metallic container (2) is closed with a metal plug (4) and the container(2) filled with the composite powder (3) to be compacted. The other end of the metallic container is closed with a metallic preferably steel plug (5). Plugs (4) and (5) have the designs as shown in fig 2(c) and 2(d) which are such that the projection of the plug fits perfectly into the bore of the metallic ^container. This aluminium metallic container (2) with composite powder (3) is axially located inside a collapsible cylindrical plastic container (1) having preferably about 84 mm internal diameter with about 3 mm wall thickness. On top end of the metallic container(2), a wooden cone (6) having preferably about 32 mm diameter base and preferably about 20 mm height is placed above the metallic plug (5), the purpose of which is to modify the shock front. The annular cavity between the metallic container (2) and the outer plastic container (1) is packed to uniform density with trimonite explosive powder (7) which contains ammonium nitrate, TNT and aluminium powder, this thickness is referred to as thickness of explosive pad. The problem of central defects in the billets is avoided by optimisation of explosive pad thickness on the annular space by selecting metallic tubes and collapsible tubes of desired dimensions. Alter filling the annular space between the metal container (2) and plastic container (1), the plastic container (1) is sealed from both the ends with two plastic lids (8) and (9). At the top end of the plastic container (1), it has a suitable hole to insert an electrical detonator (10) for detonating the explosive. According to the present invention, the preferred method for preparation of 2124 Al reinforced with upto 30 vol.% SiCp using above described apparatus is that:- (a) Firstly the lower end of the metallic container (2) is closed with metal plug (5). (b) The composite powder mix (3) is uniformly packed along the length of the container (2) and then the upper end closed by the metal plug (4). (c) This entire assembly of the container (2) is centrally placed inside the cylindrical plastic container (I) closed from the bottom side with plastic lid (8) and a wooden cone (6) is then placed at the top of the metallic container (2) in order to modify the shock front. (d) The annular cavity between the metal container (2) and the plastic container (1) is then packed to uniform density with trimonite explosive powder (7) which contains ammonium nitrate, TNT and aluminium powder. (e) The plastic container is then fitted with the top plastic lid (9) which already contains an opening for placing the electric detonator (10) in vertical position. (f) The detonator is then initialed producing convergent cylindrical shock wave which collapses the plastic container (1) and compacts the composite powder (3). (g) Fig 3(a) and fig 3(b) show the different perspective views of the components before and after the initiation of the explosive powder. It is to be understood that the above description of the present invention is susceptible to considerable modification, change and adaptation by those skilled in the art. Such modification, adaptation and change are intended to be considered to be within the scope of the present invention which is set forth by the following claims: We Claim; 1. An apparatus for production of metal matrix composite billets, reinforced with silicon carbide particularly for explosive compaction of a metal such as 2124 Aluminium alloy, reinforced with silicon carbide comprising of particulate (SiC) to produce metal matrix composite billets, comprising: a) a collapsible outer container (1) with lids (8) and (9) to close its two ends, characterized in that is; b) an inner metallic container (2) with lids (4) and (5) to close its two ends; c) an explosive powder is packed in the annular space between inner metallic container (2) and outer container (1); d) a wooden cone (6); e) an electric detonator (10) to initate producing convergent cylindrical shock waive. 2. An apparatus for producing reinforced metal matrix composite billets as claimed in claim 1 wherein said explosive powder comprises of preferably a mixture of ammonium nitrate, TNT and aluminium powder. 3. An apparatus as claimed in claim 1 wherein said cone comprises a wooden cone. 4. An apparatus as claimed in claim 1 wherein said outer container is of plastic. 5. An apparatus as claimed in claim 1 wherein said inner container is of aluminium. 6. A process for producing reinforced metal matrix composite billets using the apparatus as claimed in claim 1 which comprises in the steps of: a) packing composite powder mix in a metallic container (2) closed from both ends by metal plugs (4) and (5) and placing a cone (6) over upper end; b) placing centrally the metal container (2) inside an outer container (1) covered with the lids (8) 85 (9) from both the ends; c) filling the annular space between metal container (2) and container (1) with explosive mixture; d) detonating the explosive which compacts the composite powder placed in metallic container (2) by the convergent cylindrical shock waves thus produced and which collapses the container (1). 7. An apparatus for producing reinforced metal matrix composite billets substantially as herein described and illustrated. Dated this 10th Day of August, 1999. (YOGYATA SINGH) OF L.S.DAVAR & CO., APPLICANTS AGENT

Full Text

FILED OF INVENTION
This invention relates to process and apparatus for production of metal matrix composite billets reinforced with silicon carbide (SiCp) particulate, through explosive compaction. Though the present invention is described in relation to explosive compaction process for 2124 aluminium alloy reinforced with silicon carbide (SiCp) particulate to produce metal matrix composite billets, however, it is not intended to imply any limitation as the apparatus and process of the present invention can be used for alloys of other metals and also for other grades of aluminium besides the grade 2124 of aluminium described in the present invention.
PRIOR ART
Silicon carbide particulate reinforced aluminium metal matrix composites have higher stiffness and resistance to fatigue, creep and wear compared to many wrought aluminium alloys. These materials are receiving & great deal of attention for demanding applications in aerospace, electronic packaging and automobile industries.

Conventional powder metallurgy process for production of 2124 Al alloy-with upto 30 vol.% SiCp) metal matrix composite billets involves cold compaction followed by hot pressing which are cumbersome and experts be.
The above conventional process has the disadvantage that it involves high capital investments in equipment.
Another disadvantage of above process is that it involves undesirable long processing time.
Still another disadvantage of the above process is that it requires prolonged exposure to high temperature which in turn has the disadvantage that it shortens the life of the composites.
Further disadvantage of the above process is that the prolonged exposure to high temperature, required in these processes, leads to the formation of coarse intermetal1ic compounds which adversely affect the properties of the composites billets.
Yet further disadvantage of the above process is that it degrades the microstructure of 2124 Al alloy powders.

OBJECTS OF PRESENT INVENTION
The primary object of the present invention is to provide an explosive compaction process and an apparatus thereof, for producing metal matrix composite billets of metals in general, particularly for explosive compaction of 2124 Al alloy reinforced with silicon carbide (SiCp) particulate to produce metal matrix composite billets.
Another object of the present invention is to propose a process and an apparatus which produces metal matrix composite billets of 2124 Al with SiCp which have density comparable to that obtained by conventional hot pressing.
Still another object of the present invention is to provide a single stage process for composite powder compaction, to produce metal matrix billets, directly from the raw material, thereby eliminating the need for secondary forming operations like forging and extrusion.
Further object of the present invention is to propose a process and an apparatus which provides a

significantly economical process for producing metal matrix composite billets of 2124 Al with SiCp as it avoids the requirement of large presses and extrusion machinery.
Still further objects of the present invention is to propose a process and an apparatus which produces metal matrix composite billets of 21 24 Al with SiCp in comparatively less time as compared to the conventional process.
Yet further objects of the present invention is to propose a process and an apparatus which produces metal matrix composite billets of 2 124 Al with SiCp, wherein the original powder microstructure is retained even after the compaction process is completed.
STATEMENT OF INVENTION
According to this invention there is provided a process and apparatus for production of metal matrix composite billets, reinforced with silicon carbide, particularly for explosive compaction of a metal such as 2124 Aluminium alloy, reinforced with silicon carbide comprising of particulate (SiCp) to produce metal matrix composite billets, comprising:
a) a collapsible outer container with lids and to close its two
ends, characterized in that is; of an inner metallic container with lids and 10 close its two
ends;
c) an explosive powder is packed in the annular space between
inner metallic container and outer container;
d) a wooden cone;
e) an electric detonator to initate producing convergent
cylindrical shock waive.
Further according to this invention there is provided A process for producing reinforced metal matrix composite billets using the apparatus as claimed in claim 1 which comprises in the steps of:
a) packing composite powder mix in a metallic container closed
from both ends by metal plugs and and placing a cone over
upper end;
b) placing centrally the metal container inside an outer
container covered with the lids from both the ends;
c) filling the annular space between metal container and
container with explosive mixture;
d) detonating the explosive which compacts the composite
powder placed in metallic container by the convergent
cylindrical shock waves thus produced and which collapses
the container.

The present invention provides a process and an apparatus by which reinforced metal matrix composites like metal matrix composites of 2124 Aluminium alloy reinforced with upto 30 vol% of silicon carbide paniculate can be compacted through explosive compaction to produce metal matrix composite billets. The invention uses energy of shock waves generated through detonating an explosive powder to compact the composite powder to produce metal matrix composites. The apparatus involves two coaxial cylinders with inner cylinder as metallic cylinder,; preferably aluminium cylinder and the outer cylinder , made of plastic. The inner cylinder is packed with composite powder to be explosive-compacted while annular space between the two cylinders is filled with required explosive composition A wooden cone on the top of the inner cylinder enables modification of shock front. The explosive powder- is detonated with an " electrical detonator provided at the top of apparatus. The metal matrix composite produced by explosive compaction through the apparatus of the present invention is significantly economical as it avoids the use of expensive large presses. The explosive compaction through the apparatus of the present invention enables the production of metal matrix composites directly from raw material thereby eliminating secondary forming operations like forging and extrusion. The density of metal matrix composites produced through the apparatus of the present invention is comparable to the metal matrix composites produced through the conventional hot pressing and extrusion. The explosive compaction through the apparatus of the present invention also takes less lime as compared to processes known in the art and also results in the microstructure having original dendritic structure of the matrix metal with a uniform distribution of reinforcement particles all around the matrix metal particles.
PRESCRIPTION OF FIGURES
The objects of the present invention will be more clearly understood from the following detailed description in conjunction with the accompanying drawings which show an illustrative embodiment of the apparatus which is not intended to imply any limitation, in any way, on the scope of the present invention. In the accompanying drawings of the apparatus for carrying out explosion process, the different figures depict as follows:-

Figure 1: shows the complete assembly of the
apparatus
Figure 2(a) shows front view of metallic
(aluminium) container;
Figure 2(b) shows top view of metallic container;
Figure 2(c) & 2(d) shows front view of the two metallic
plugs used to close the metallic container from bottom-end and upper-end.
Figure 2(e) shows top view of the two metallic
plugs;
Figure 2(f) shows the front view of the wooden
cone;
Figure 2(g) shows the bottom view of the
wooden cone
Figure 2(h) shows front view of the outer
plastic container;
Figure 2(i) shows top view of the outer
plastic container;
Figure 2(k) & 2(1) shows front view of top plastic
cover plates for closing the two ends of plastic container;
Figure 2(m) shows top view of plastic cover
plates for closing the two ends of plastic container;
Figure 2(n) shows the electric detonator.

DESCRIPTION OF THE APPARATUS WITH REFERENCE TO DRAWINGS
The process of the present invention will now be described with respect to the accompanying figures. Referring to Fig 1, the apparatus for producing metal matrix composite billets comprises of cylindrical metal container (2), preferably aluminium container having preferably about 26 mm internal diameter with 3 to 5 mm wall thickness. One end of the metallic container (2) is closed with a metal plug (4) and the container(2) filled with the composite powder (3) to be compacted. The other end of the metallic container is closed with a metallic preferably steel plug (5). Plugs (4) and (5) have the designs as shown in fig 2(c) and 2(d) which are such that the projection of the plug fits perfectly into the bore of the metallic ^container. This aluminium metallic container (2) with composite powder (3) is axially located inside a collapsible cylindrical plastic container (1) having preferably about 84 mm internal diameter with about 3 mm wall thickness. On top end of the metallic container(2), a wooden cone (6) having preferably about 32 mm diameter base and preferably about 20 mm height is placed above the metallic plug (5), the purpose of which is to modify the shock front. The annular cavity between the metallic container (2) and the outer plastic container (1) is packed to uniform density with trimonite explosive powder (7) which contains ammonium nitrate, TNT and aluminium powder, this thickness is referred to as thickness of explosive pad. The problem of central defects in the billets is avoided by optimisation of explosive pad thickness on the annular space by selecting metallic tubes and collapsible tubes of desired dimensions. Alter filling the annular space between the metal container (2) and plastic container (1), the plastic container (1) is sealed from both the ends with two plastic lids (8) and (9). At the top end of the plastic container (1), it has a suitable hole to insert an electrical detonator (10) for detonating the explosive.

According to the present invention, the preferred method for preparation of 2124 Al reinforced with upto 30 vol.% SiCp using above described apparatus is that:-
(a) Firstly the lower end of the metallic container (2) is closed with
metal plug (5).
(b) The composite powder mix (3) is uniformly packed along the
length of the container (2) and then the upper end closed by the
metal plug (4).
(c) This entire assembly of the container (2) is centrally placed
inside the cylindrical plastic container (I) closed from the
bottom side with plastic lid (8) and a wooden cone (6) is then
placed at the top of the metallic container (2) in order to modify
the shock front.
(d) The annular cavity between the metal container (2) and the
plastic container (1) is then packed to uniform density with
trimonite explosive powder (7) which contains ammonium
nitrate, TNT and aluminium powder.
(e) The plastic container is then fitted with the top plastic lid (9)
which already contains an opening for placing the electric
detonator (10) in vertical position.
(f) The detonator is then initialed producing convergent cylindrical
shock wave which collapses the plastic container (1) and
compacts the composite powder (3).
(g) Fig 3(a) and fig 3(b) show the different perspective views of the
components before and after the initiation of the explosive
powder.
It is to be understood that the above description of the present invention is susceptible to considerable modification, change and adaptation by those skilled in the art. Such modification, adaptation and change are intended to be considered to be within the scope of the present invention which is set forth by the following claims:

We Claim;
1. An apparatus for production of metal matrix composite billets,
reinforced with silicon carbide particularly for explosive
compaction of a metal such as 2124 Aluminium alloy,
reinforced with silicon carbide comprising of particulate (SiC) to
produce metal matrix composite billets, comprising:
a) a collapsible outer container (1) with lids (8) and (9) to close
its two ends, characterized in that is;
b) an inner metallic container (2) with lids (4) and (5) to close
its two ends;
c) an explosive powder is packed in the annular space between
inner metallic container (2) and outer container (1);
d) a wooden cone (6);
e) an electric detonator (10) to initate producing convergent
cylindrical shock waive.

2. An apparatus for producing reinforced metal matrix composite
billets as claimed in claim 1 wherein said explosive powder
comprises of preferably a mixture of ammonium nitrate, TNT
and aluminium powder.
3. An apparatus as claimed in claim 1 wherein said cone
comprises a wooden cone.
4. An apparatus as claimed in claim 1 wherein said outer
container is of plastic.
5. An apparatus as claimed in claim 1 wherein said inner
container is of aluminium.

6. A process for producing reinforced metal matrix composite
billets using the apparatus as claimed in claim 1 which
comprises in the steps of:
a) packing composite powder mix in a metallic container (2)
closed from both ends by metal plugs (4) and (5) and placing
a cone (6) over upper end;
b) placing centrally the metal container (2) inside an outer
container (1) covered with the lids (8) 85 (9) from both the
ends;
c) filling the annular space between metal container (2) and
container (1) with explosive mixture;
d) detonating the explosive which compacts the composite
powder placed in metallic container (2) by the convergent
cylindrical shock waves thus produced and which collapses
the container (1).
7. An apparatus for producing reinforced metal matrix composite
billets substantially as herein described and illustrated.
Dated this 10th Day of August, 1999.

(YOGYATA SINGH) OF L.S.DAVAR & CO., APPLICANTS AGENT

Documents:

967-del-1999-abstract.pdf

967-del-1999-claims.pdf

967-del-1999-correspondence-others.pdf

967-del-1999-correspondence-po.pdf

967-del-1999-description (complete).pdf

967-del-1999-drawings.pdf

967-del-1999-form-1.pdf

967-del-1999-form-19.pdf

967-del-1999-form-2.pdf

967-del-1999-form-3.pdf

967-del-1999-gpa.pdf

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Patent Number

230895

Indian Patent Application Number

967/DEL/1999

PG Journal Number

13/2009

Publication Date

27-Mar-2009

Grant Date

28-Feb-2009

Date of Filing

13-Jul-1999

Name of Patentee

THE CHIEF CONTROLLER , RESEARCH AND DEVELOPMENT

Applicant Address

MINISTRY OF DEFENCE, GOVT OF INDIA, B-341, SENA BHAWAN, DHQ P.O., NEW DELHI-110011, INDIA.

Inventors:

#	Inventor's Name	Inventor's Address
1	KANDIKATTU SIVA KUMAR	DEFENCE METALLURGICAL RESEARCH LAB, HYDERABAD
2	TALAPADY BALAKRISHNA BHAT	DEFENCE METALLURGICAL RESEARCH LAB, HYDERABAD

PCT International Classification Number

G21C 21/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA