Title of Invention

" A PROCESS FOR PRODUCTION OF METAL MATRIX COMPOSITE TUBES".

Abstract

This invention relates to an device for the production of metal matrix composite tubes by an explosive compaction process which makes use of shock energy produced through the detonation of explosive powder for compaction of a composite powder. The device comprises a collapsible outer plastic container having a lower lid adapted to close the lower end of said container and an upper lid adapted to close the upper end of said container. An inner container is disposed within and spaced from said outer container. A cone is disposed between said inner and outer container. A cylindrical mendrel is disposed within said inner container. An electrical detonator and an explosive powder packed within said outer and inner container. Further according to the process of this invention one end of a metallic container is closed with a metallic plug and a mendrel is disposed within the container. The annulair space between metal container and mendrel is packed with a composite powder to be compacted and closing the upper end with a plug. A cone is placed on the top end of the metal container. The lower end of container is closed with a cover and placed centrally inside it, the assembly as prepared. The annular space between inner assembly and container is packed with an explosive powder and closing the upper end with cover having a hole in which electrical detontor is fixed. The explosive powder is detonated by electrical detonator which produces shock energy which compacts the composite powder and the mendrel is removed.

Full Text

A PROCESS AND AN APPARATUS FOR PRODUCTION OF METAL MATRIX COMPOSITE TUBES FIELD OF INVENTION This invention relates to a process for production of metal matrix composite tubes. More particularly the process relates to a process which uses energy of shock waves generated through the detonation of an explosive powder to compact a composite powder to produce metal matrix composite tubes/tubular components. PRIOR ART; Conventional processes for production of metal matrix composite tubes involve cumbersome and expensive techniques like cold compaction, hot pressing and extrusion. One of the disadvantage of these conventional processes is that these processes involve high capital investments. Another disadvantage of the known processes is that these processes involve long processing times. Still another disadvantage of the known processes is that prolonged exposure to high temperature leads to the formation of coarse intermetallic compounds which adversely affect the properties of the composite tubes and the life of i the component is affected severely. Yet further disadvantage of the conventional processes is that in these processes there occurs degradation of the microstructure of the original powders. OBJECTS OF PRESENT INVENTION: The primary and the main object of the present invention is to provide an apparatus by which the powders of matrix and reinforcement materials can be compacted directly into the hollow tubular components. Another object of the present invention is to provide an explosive compaction process for producing metal matrix composite tubes of improved quality using shock energy produced through detonation of an explosive. Still another object of the present invention is to propose an explosive compaction process which produces metal matrix composite tubes of density almost similar to that obtained by conventional hot pressing and extrusion. Further object of the present invention is to propose an explosive compaction process which enables production of metal matrix composite tubes with higher volume percentages of the reinforcement of ceramic material to the extent of 50 percent by volume, which are difficult to produce by conventional processes. Still further object of the present invention is to propose a process for producing metal matrix composite tubes, which is significantly economical as it avoids the requirement of large presses and extrusion machinery. Yet further object of the present invention is to propose an explosive compaction process which enables production of composite components directly from the raw material whereby eleminating the secondary forming operations like forging and extrusion. Still further object of the present invention is to propose a process for production of metal matrix composites which takes comparatively less time for the production of tubes as compared to the conventional processes. Yet further object of the present invention is to propose a process for production of metal matrix composites wherein the original powder microstructure is retained even after the compaction process is completed., DESCRIPTION OF INVENTION According to this invention there is provided an apparatus for production of metal matrix composite tubes by an explosive compaction process which makes use of shock energy produced through the detonation of explosive powder for compaction of a composite powder comprising: a ) a collapsible outer p 1 astic: container (1) having a lower lid (9) adapted to close UK lower end of said container and an upper lid (10) adapted to close the upper end of said container: b) an inner container (2) disposed within and spaced from said outer container; c) a cone (7) disposed between said inner and outer container; d) a cylindrical mendrel (3) disposed within said inn e r c o n t a i n e r ; e) an electrical detonator (11), and f) an explosive powder packed within' said outer and inner container. Further, according to this invention there is provided a process for production of metal matrix composite tubes by an explosive compaction which comprises s a) closing one end of a metallic container (2) with metallic plug(6) and disposing a mend re .1. (3) within said c on t a i n e r; b) packing in the annulalr space between metal container (2.) and mend re 1 (3) a composite powder (4) to be compacted and closing the upper end with plug (5); c) placing cone (7) on the top end of the metal container (2); d) closing lower end of container (1) with a cover (9) and placing centrally inside it, the assembly as prepared from step (a) to (c); e) packing in the annular space between inner assembly and container (.1.) with an explosive powder (8) and closing the upper end with cover (.1.0) having a hole in which electrical de ton tor (.11) is fixed; f) detonating the explosive powder by electrical detonator (11) which produces shock energy which compacts the composite powder; g) removing the mendrel. DESCRIPTION WITH REFERENCE TO ACCOMPANYING DRAWINGS Fig.l shows the complete assembly of the apparatus Fig.2 shows the black diagrams of different components of the apparatus wherein; Fig.2(a) shows top view and front view of cylindrical core called 'mendre1' Fig.2(b) shows top view and front view of metallic (a 1 u m i n i u m) c on t a i n e r Fig.2(c) shows top view and front view of metallic plugs used to close the metallic container Fig.2(d) shows the front view and bottom view wooden cone Fig.2(e) shows front view and top view of the outer p1as t i c c on tain e r Fig.2(f) shows front view and top view of top plastic cover plates for closing the two ends of p 1 a s t i. c: c o n t a i n e r Fig.2(g) shows the electric detonator-Fig .3 shows the tube produced by com paction process of the present invention using aluminium reinforced with SiC particulats- (2124 A1--20 Vol/SiCp) and water soluble mandrel Fig.4 shows the micro structure of the tube produced by the process of the present invention wherein: Fig.4(a) shows distribution of silicon carbide particles around aluminium particles F i g . 4 ( b ) s h o w s t h e o r i g i n a 1 d e n d i r i t i c m i. c.: r o structure i n s i d e t he pa r t i. c 1 e . DESCRIPTION OF APPARATUS Referring to Fig. 1, the apparatus for producing metal matrix composite tubes comprises of a cylindrical metallic container 2, preferably aluminium container,, which is axial ly located inside a collapsible cylindrical outer container 1. Container 1 may by way of example be of plastic. The metallic container 2 has a working example 20 .to 40mm internal diameter with 3 to 5mm wall thickness. A cylindrical core mandrel 3, made up of commercial wax or commercial salt,, is centrally located inside the metallic container 2,, The annular space between the mandrel 3 and the metallic container 2 is filled uniformly with the composite powder 4 to be compacted. After filling the container 2 with the powder mixture, two ends of metallic container are closed with the metallic plug 5 and 6. These plug 5 and 5 have the designs as shown in Fig. 2(c.) which are such that the projection of the plug perfectly fits into the bore of the metallic container 2. On the top end of the metallic container 2, a cone 7 ,, such as of wood is placed above the metallic, plug 5, the purpose of which is to modify the shock front. The annual cavity between the metallic container 2, wooden cone 7 and the outer plastic container 1 is packed to uniform density with explosive powder 8 containing ammonium nitrate,, TNT and a 1 u m i n i u m p o w d e r . A f t e r f i 11 i n g t h e 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 (9) and (10) . The plastic cap (to) at the top end of the plastic container (1), has a hole to insert an electrical detonator (11) for detonation of the explosive. DESCRIPTION OF PROCESS According to the process of the present invention using the above-described apparatus, firstly the lower end of the metallic container (2) is closed with the metal plug (6) . Thereafter the mandrel (3) is placed at the centre of metallic container(2). The composite powder mix (4) is packed to uniform density along the length of the container (2) in the annular space between the metal container (2) and the mendrel (3). Subsequently the metal container (2) is closed on the upper end by the metal plug (5). This entire assembly is placed centrally inside the cylindrical plastic container (1) which has been closed at lower end by plastic cap (9) . A wooden cone (7) is then placed at the top of the metallic container (2) in order to modify the shock front. The annular cavity between the metal container (2) and plastic container (1) is then packed to uniform density with explosive powder (8)containing ammonium nitrate containg TNT and aluminium powder. The upper end of the plastic container is closed with plastic cap (10). The electrical detonator (II) is fixed in the hole at the centre of the plastic cap (11) . The detonation of the explosive charge is done with electrical detonator (11) in the vertical position. This produces a convergent cylindrical shock wave which collapses the plastic container (1) and dompacts the composite powder (4) . After compaction, the salt mandrel are removed by dissolving in water and the wax mendrel are removed by heating the compact. Fig2(a) to 2(g) show the different perspective viqws of the components used in the apparatus shown in fig 1. Aluminium reinforced with Sic particulates was compacted using soluble mandrel. The tube produced is shown in Fig. 3. The tube was cut and its microstructure was studied. In these experiments distribution of SiC particulates was found to be uniform throughout the sample. This is evident from the microstruture shown in Fig.4. "• v It is to be understood that the above description of the present invention is susceptible to considerable modifications, change and adaptation by those skilled in the art. Such modifications are intended to be considered to be within the scope of the present invention, which is set forth by the following claims:- I CLAIM; 1. An apparatus for production of metal matrix composite tubes by an explosive compaction process which makes use of shock energy produced through the detonation of explosive powder for compaction of a composite powder comprising : a). a c o 11 a p s i b 1 e ou t e r p 1 a s t i c c o nt a i n e r (1) having a lower lid (9) adapted to close the lower end of said container and an upper lid (10) adapted to close the upper end of said container: b) an inner container (2) disposed within and spaced from said outer container; c) a cone (7) disposed between said inner and o u t er c o n t a i.n er ; d ) ax c y 1 i n d r i. c a 1 me n d r e 1 (3) disposed within s a i d inner con t a i n e r ; e) an electrical detonator (11), and f) an explosive powder packed within said outer and inner container. 2. An apparatus as claimed in claim 1 wherein said inner container (2) has an upper plug (5) and a 1ower plug (6). 3. An apparatus as claimed in claim 1 wherein said container (2) is a metallic container. 4. An apparatus as claimed in claim i wherein said cone (7) is disposed above of said metallic container. 5. An apparatus as claimed in claim 1 wherein said explosive is a mixture of TNI, ammonium nitrate and a 1.um i n i u m p o w d e r. 6. An apparatus as claimed in claim 1 wherein said mandrel is of wax/salt. 7. An apparatus as claimed in claim 1 wherein said container is disposed coaxially within said outer container. 8. An apparatus for production of metal matrix composite tubes substantially as herein described and i1lustrated. 9. A process for production of metal matrix composite taubes by an explosive compaction which comprises: a) closing one end of a metallic container (2) with metallic plug(6) and disposing a. mendrel. (3) within s a i d c o n t a i n e r ; b) packing in the annulalr space between metal c o n t a i n e r ( 2 ) a n d m e n d r e 1 ( 3 ) a c o m posite p o w d e r ( 4 ) to be compacted and closing the upper end with plug (5); c) placing cone (7) on the top end of the metal container (2); d) closing lower end of container (1) with a cover (9) and placing centrally inside it, the assembly as prepared from step (a) to (c); e) packing in the annular space between inner assembly and container (1) with an explosive powder (8) and closing the upper end with cover (10) having a hole in which electrical detontor (11) is fixed; f) detonating the explosive powder by electrical d e t o n a to r (11) w h i c h p r o d u c e s s h o ck e n e r g y which c o m p a ct s the comp os i t e p o w d e r ; g) removing the mendrel. 10. A process as claimed in claim 9 wherein the explosive preferably used for producing shock, energy for compaction of the composite powder is a mixture of TNT, ammonium nitrate, and aluminium powder. 11. A process as claimed in claims 9 & 10 wherein said inner container is disposed coaxially within said ou t e r c o n t a i n e r . 12. A process as claimed in claims 7 to 11 wherein said mandrel is of salt/walk. 13. A process as claimed in claim 9 wherein said salt mandrel is removed by disolving in water or by heating the compact for wax mandrel., 14. A process for the production of metal matrix composite tubes substantially as herein described and i1lustrated.

Documents:

54-del-1997-abstract.pdf

54-del-1997-claims.pdf

54-DEL-1997-Correspondence-Others-(03-12-2009).pdf

54-del-1997-correspondence-others.pdf

54-del-1997-correspondence-po.pdf

54-del-1997-description (complete).pdf

54-del-1997-drawings.pdf

54-del-1997-form-1.pdf

54-del-1997-form-13.pdf

54-DEL-1997-Form-15-(03-12-2009).pdf

54-del-1997-form-19.pdf

54-del-1997-form-2.pdf

54-del-1997-form-3.pdf

54-del-1997-gpa.pdf