Title of Invention	A NOVEL PROCESS FOR THE FABRICATION OF MG-30% SIC PARTICLE REINFORCED COMPOSITES BY CASTING ROUTE
Abstract	ABSTRACT Disclosed herein is a novel process for the fabrication of Mg-30% SiC particle reinforced composites by casting route comprising the steps of melting of metal such as magnesium, incorporating the preheated ceramic into the melted magnesium and mixing of aforesaid materials homogeneously, characterized in that the said process is carried out without flux and without the use of protective inert gas atmosphere.

Title of Invention

A NOVEL PROCESS FOR THE FABRICATION OF MG-30% SIC PARTICLE REINFORCED COMPOSITES BY CASTING ROUTE

Abstract

ABSTRACT Disclosed herein is a novel process for the fabrication of Mg-30% SiC particle reinforced composites by casting route comprising the steps of melting of metal such as magnesium, incorporating the preheated ceramic into the melted magnesium and mixing of aforesaid materials homogeneously, characterized in that the said process is carried out without flux and without the use of protective inert gas atmosphere.

Full Text	FIELD OF TECHNOLOGY This invention in general relates to the field of metallurgical technology. Further this invention relates to the field of metal process. More particularly this invention relates to a novel process for the fabrication of Mg - 30%, SiC particle reinforced composites by casting route. The Following specifications describe the nature of this invention: PRESENT STATE OF ART Ceramic particle reinforced Magnesia, and Mg alloy matrix composites are currently an ideal choice for aerospace and other applications because of their low density and superior stiffness. In addition SiC ceramic reinforcement of Mg and Mg alloy could lead to improvement in room an elevated temperature synthesis apart from improvement in wear resistance and damping capacity. In general, MMCs based on Mg and its alloy reinforced with SiC has been produced by stir casting, powder metallurgy and squeeze casting. However, all these processes are either tedious and or expensive. Hence, there is a need to develop affordable and easily adaptable casting process for the synthesis of SiC particle reinforced Mg composites. LIMITATIONS The following specification describes in details the various aspects of prior art technology, shortcomings in the prior art process & technology and the invention addresses the problem associated with prior art technology. The invention proposes a solution to overcome the problem associated with prior art methods and systems. This is reflected in the objects of the invention. Existing processing relies on the use of either flux or protective inert gas atmosphere. Very often SF6/CO2 protective inert gas atmosphere is also used for melting and casting of Mg based composites. Hence, there is an imperative need to develop a process for making Mg-Ceramic particle composites without the use of the protective inert gas. Accordingly, it is the primary object of invention to design and develop a process for fabrication of Mg-30%, SiC particle reinforced composites by casting route eliminating the use of flux or protective inert gas. Another object of the invention is to produce high modulus, high strength and high wear resistance silicon carbide reinforced magnesium composite. Further object of the invention is to enhance the elevated temperature strength of pure magnesium at least up to 250°C by reinforcing with SiC particles. Another objective is to develop process for incorporating SiC particles into pure magnesium melt without the use of Argon or salt-based fluxes. Further objects of the invention will be clear from the following description. This invention thus provides a novel process for the fabrication of Mg-30% SiC particle reinforced composites by casting route comprising the steps of: (a) Melting ofmetal such as Magnesium; (b) Incorporating the preheated ceramic into the melted magnesium; and (c) Mixing of aforesaid materials homogeneously, characterized in that the said process is carried out without flux and without the use of protective inert gas atmosphere. The nature of the invention and the manner in which it is to be performed is clearly described in the following description. The magnesium 30 vol. SiCp composite was processed by melt stir technique. The matrix material was 99 % pure magnesium and SiC particles with 40 μm average size. Steps involved and the procedure employed for the fabrication of composites are as follows. The melting was carried out using a resistance-heating furnace 1 of 5 KW. Stainless steel crucible 2 with a capacity to hold 5 Kg of Mg was used for melting Mg and subsequent processing of composites. Magnesium ingot 3 weighing about 2.5 KG was fully wrapped with aluminum foil and charged into the stainless steel crucible 2. During melting the furnace was covered with lid 4 as shown in Fig. 1 of the accompanying drawing. This is done to minimize contact between the atmospheric oxygen and Mg metal. In addition aluminum foil (used for wrapping Mg metal) helped to prevent oxidation and burning of magnesium metal. Temperature was monitored and controlled closely and care was taken to maintain the furace temperature around 700°C. The metal was melted with very little oxidation. This was quickly followed by the additions of pre heated SiC particles through the inlet 5 into the vortex of the melt created by the rotating impeller 6. The shafl 7 of the impeller is connected to a motor 8 placed on a supporting frame 9. A complete addition of SiC particles was done in less than a minute. During this period very little burning was observed on the surface of the melt. The composite melt was poured into the cast iron cylindrical mold of 65 mm diameter and 200 mm height. The material loss incurred by this method was less than 15 wt.%. PROPOSED SOLUTION A method is proposed, to melt and process 30% SiC reinforced Mg metal composites without the use of flux or protective gas environment. The method involves modified procedure for melting of Magnesium and subsequent incorporation of pre-heated ceramic particles into molten Magnesium and their mixing. Composites thus processed possess superior stiffness and enhanced strength at elevated temperatures. Fig.1 shows the schematic of the set up used. It consists of resistance heating furnace of 5 kW. Stainless steel crucible with a capacity to hold 5Kg of Magnesium was used for melting Mg and subsequent processing of composites. Mg ingots wrapped with aluminum foil are charged into the stainless steel crucible. During melting the furnace was covered into stainless steel crucible. It is to be understood that the description clearly describes various aspects of the invention and construded such that the description is in no way limiting the scope of the invention. It is to be further understood that within the scope of the invention various modifications are permissible. The statement of claims is described in the following description. ADVANTAGE OF THE INVENTION 1. It is possible to incorporate up to 30 vol% SiC particles of average size 40 μm into molten, magnesium kept at 700°C or slightly below that. Ceramic particle incorporation can be achieved without the use of flux or argon atmosphere. 2. SiC dispersed magnesium melt slurry can be cast into solid ingots in cast iron 3. Hardness, 0.2 % proof stress, UTS and elastic modulus of Mg-30% SiC composites thus prepared are at least 30% higher compared to unreinforced pure magnesium at room temperature. 4. 0.2% proof stress and UTS of Mg-30% SiC composites at 250°C are higher at least by 30% compared to unreinforced pure magnesium. I Claim: 1. A novel process for the fabrication of Mg-30% SiC particle reinforced composites by casting route comprising the steps of: (a) Melting of metal such as Magnesium; (b) Incorporating the preheated ceramic into the melted magnesium; and (c) Mixing of aforesaid materials homogeneously, characterized in that the said process is carried out without flux and without the use of protective inert gas atmosphere, 2. A process as claimed in claim 1, wherein the Mg based SiC reinforced composite with superior wear resistance properties is produced. 3. A process as claimed in claim 1, wherein the elevated temperature strength of pure magnesium is enhanced by at least 250°C by reinforcing with SiC particles. 4. A process as claimed in claim 1, wherein the SiC particles are incorporated into pure magnesium melt without the use of Argon or salt based fluxes. 5. A novel process for the fabrication of Mg-30% SiC particle reinforced composites by casting route substantially as herein before described and illustrated in the accompanying drawing.

Full Text

FIELD OF TECHNOLOGY
This invention in general relates to the field of metallurgical technology. Further this invention relates to the field of metal process. More particularly this invention relates to a novel process for the fabrication of Mg - 30%, SiC particle reinforced composites by casting route.
The Following specifications describe the nature of this invention:
PRESENT STATE OF ART
Ceramic particle reinforced Magnesia, and Mg alloy matrix composites are currently an ideal choice for aerospace and other applications because of their low density and superior stiffness. In addition SiC ceramic reinforcement of Mg and Mg alloy could lead to improvement in room an elevated temperature synthesis apart from improvement in wear resistance and damping capacity.
In general, MMCs based on Mg and its alloy reinforced with SiC has been produced by stir casting, powder metallurgy and squeeze casting. However, all these processes are either tedious and or expensive. Hence, there is a need to develop affordable and easily adaptable casting process for the synthesis of SiC particle reinforced Mg composites.
LIMITATIONS
The following specification describes in details the various aspects of prior art technology, shortcomings in the prior art process & technology and the invention addresses the problem associated with prior art technology. The invention proposes a solution to overcome the problem

associated with prior art methods and systems. This is reflected in the objects of the invention.
Existing processing relies on the use of either flux or protective inert gas atmosphere. Very often SF6/CO2 protective inert gas atmosphere is also used for melting and casting of Mg based composites. Hence, there is an imperative need to develop a process for making Mg-Ceramic particle composites without the use of the protective inert gas.
Accordingly, it is the primary object of invention to design and develop a process for fabrication of Mg-30%, SiC particle reinforced composites by casting route eliminating the use of flux or protective inert gas.
Another object of the invention is to produce high modulus, high strength and high wear resistance silicon carbide reinforced magnesium composite.
Further object of the invention is to enhance the elevated temperature strength of pure magnesium at least up to 250°C by reinforcing with SiC particles.
Another objective is to develop process for incorporating SiC particles into pure magnesium melt without the use of Argon or salt-based fluxes.
Further objects of the invention will be clear from the following description.
This invention thus provides a novel process for the fabrication of Mg-30% SiC particle reinforced composites by casting route comprising the steps of:
(a) Melting ofmetal such as Magnesium;
(b) Incorporating the preheated ceramic into the melted magnesium; and
(c) Mixing of aforesaid materials homogeneously,
characterized in that the said process is carried out without flux and without the use of protective inert gas atmosphere.

The nature of the invention and the manner in which it is to be performed is clearly described in the following description.
The magnesium 30 vol. SiCp composite was processed by melt stir technique. The matrix material was 99 % pure magnesium and SiC particles with 40 μm average size. Steps involved and the procedure employed for the fabrication of composites are as follows.
The melting was carried out using a resistance-heating furnace 1 of 5 KW. Stainless steel crucible 2 with a capacity to hold 5 Kg of Mg was used for melting Mg and subsequent processing of composites. Magnesium ingot 3 weighing about 2.5 KG was fully wrapped with aluminum foil and charged into the stainless steel crucible 2. During melting the furnace was covered with lid 4 as shown in Fig. 1 of the accompanying drawing. This is done to minimize contact between the atmospheric oxygen and Mg metal. In addition aluminum foil (used for wrapping Mg metal) helped to prevent oxidation and burning of magnesium metal. Temperature was monitored and controlled closely and care was taken to maintain the furace temperature around 700°C. The metal was melted with very little oxidation. This was quickly followed by the additions of pre heated SiC particles through the inlet 5 into the vortex of the melt created by the rotating impeller 6. The shafl 7 of the impeller is connected to a motor 8 placed on a supporting frame 9. A complete addition of SiC particles was done in less than a minute. During this period very little burning was observed on the surface of the melt. The composite melt was poured into the cast iron cylindrical mold of 65 mm diameter and 200 mm height. The material loss incurred by this method was less than 15 wt.%.

PROPOSED SOLUTION
A method is proposed, to melt and process 30% SiC reinforced Mg metal composites without the use of flux or protective gas environment.
The method involves modified procedure for melting of Magnesium and subsequent incorporation of pre-heated ceramic particles into molten Magnesium and their mixing. Composites thus processed possess superior stiffness and enhanced strength at elevated temperatures.
Fig.1 shows the schematic of the set up used. It consists of resistance heating furnace of 5 kW. Stainless steel crucible with a capacity to hold 5Kg of Magnesium was used for melting Mg and subsequent processing of composites. Mg ingots wrapped with aluminum foil are charged into the stainless steel crucible. During melting the furnace was covered into stainless steel crucible.
It is to be understood that the description clearly describes various aspects of the invention and construded such that the description is in no way limiting the scope of the invention. It is to be further understood that within the scope of the invention various modifications are permissible. The statement of claims is described in the following description.
ADVANTAGE OF THE INVENTION
1. It is possible to incorporate up to 30 vol% SiC particles of average size 40 μm into molten, magnesium kept at 700°C or slightly below that. Ceramic particle incorporation can be achieved without the use of flux or argon atmosphere.

2. SiC dispersed magnesium melt slurry can be cast into solid ingots in cast iron
3. Hardness, 0.2 % proof stress, UTS and elastic modulus of Mg-30% SiC composites thus prepared are at least 30% higher compared to unreinforced pure magnesium at room temperature.
4. 0.2% proof stress and UTS of Mg-30% SiC composites at 250°C are higher at least by 30% compared to unreinforced pure magnesium.

I Claim:
1. A novel process for the fabrication of Mg-30% SiC particle reinforced
composites by casting route comprising the steps of:
(a) Melting of metal such as Magnesium;
(b) Incorporating the preheated ceramic into the melted magnesium; and
(c) Mixing of aforesaid materials homogeneously,
characterized in that the said process is carried out without flux and without the use of protective inert gas atmosphere,
2. A process as claimed in claim 1, wherein the Mg based SiC reinforced
composite with superior wear resistance properties is produced.
3. A process as claimed in claim 1, wherein the elevated temperature strength of
pure magnesium is enhanced by at least 250°C by reinforcing with SiC
particles.
4. A process as claimed in claim 1, wherein the SiC particles are incorporated
into pure magnesium melt without the use of Argon or salt based fluxes.
5. A novel process for the fabrication of Mg-30% SiC particle reinforced
composites by casting route substantially as herein before described and
illustrated in the accompanying drawing.

Documents:

0932-mas-1999 abstract-duplicate.pdf

0932-mas-1999 abstract.pdf

0932-mas-1999 claims-duplicate.pdf

0932-mas-1999 claims.pdf

0932-mas-1999 correspondence-others.pdf

0932-mas-1999 correspondence-po.pdf

0932-mas-1999 description(complete)-duplicate.pdf

0932-mas-1999 description(complete).pdf

0932-mas-1999 drawings-duplicate.pdf

0932-mas-1999 drawings.pdf

0932-mas-1999 form-1.pdf

0932-mas-1999 form-13.pdf

0932-mas-1999 form-19.pdf

0932-mas-1999 form-26.pdf

0932-mas-1999 form-4.pdf

0932-mas-1999 form-5.pdf

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Patent Number

193681

Indian Patent Application Number

932/MAS/1999

PG Journal Number

30/2009

Publication Date

24-Jul-2009

Grant Date

Date of Filing

21-Sep-1999

Name of Patentee

THE REGISTRAR, INDIAN INSTITUTE OF SCIENCE,

Applicant Address

BANGALORE-560 012.

Inventors:

#	Inventor's Name	Inventor's Address
1	SURAPPA, PRO M. K.,	DEPT OF METALLURGY, INDIAN INSTITUTE OF SCIENCE, BANGALORE - 560 012.
2	SARAVANAN DR. R. A.,	DEPT OF METALLURGY, INDIAN INSTITUTE OF SCIENCE, BANGALORE - 560 012.

PCT International Classification Number

C04B9/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA