METHOD OF MAKING TITANIUM ALLOY BASED AND TiB REINFORCED COMPOSITE PARTS BY POWDER METALLURGY PROCESS
A method of preparing a titanium-based metal matrix composite. In one form, titanium hydride can be added to substantially pure titanium, an alloying material and a source of boron such that a mixture of these materials can be compacted and sintered in a powder metallurgy process to produce a component made up of a titanium boride reinforced titanium alloy. In another form, the substantially pure titanium, alloying material and source of boron could be vigorously mixed (with or without the titanium hydride) to such an extent that oxide films that may have built up on the titanium precursor can be removed to minimize the presence of oxygen in the manufactured component.
1 . A method of making a composite component that includes a titanium alloy matrix and a titanium diboride reinforcement, said method comprising:
mixing a plurality of precursor materials comprising substantially pure titanium, titanium hydride, an alloying material and a boron source material;
compacting said mixture; and
sintering said compacted mixture such that during said sintering, said boron source material reacts with said substantially pure titanium to produce titanium boride and said titanium hydride becomes activated to react with any oxygen present in said mixture.
2 . The method of claim 1 , wherein said precursor materials are in powder form.
3 . The method of claim 2 , wherein said mixing further comprises removing at least a portion of any oxygen-based material formed on a surface of said substantially pure titanium.
4 . The method of claim 3 , wherein said removing comprises placing said plurality of precursor materials in an inert environment and subjecting them to rotational mixing until such time as
5 . The method of claim 4 , wherein said rotational mixing comprises rotational speeds of at least approximately 3600 revolutions per minute for a duration of at least approximately four hours.
6 . The method of claim 1 , wherein said matrix is selected from the group consisting of beta titanium, alpha-2 titanium, gamma titanium and combinations thereof.
7 . The method of claim 6 , wherein said mixture comprises between approximately three and seven ten percent by weight titanium hydride.
8 . The method of claim 1 , wherein said heating occurs at a rate of up to five degrees Celsius per minute.
9 . The method of claim 1 , wherein said alloying material comprises aluminum and vanadium.
10 . The method of claim 1 , wherein said boron source material comprises titanium diboride.
11 . The method of claim 1 , wherein said component comprises an automotive component.
12 . The method of claim 11 , wherein said automotive component is selected from the group consisting of valves, retainers, valve springs, connecting rods, bolts, fasteners, coil suspension springs and exhaust system.
13 . The method of claim 1 , further comprising at least one post-sintering surface-modifying operation.
14 . The method of claim 13 , wherein said at least one post-sintering surface-modifying operation is selected from the group consisting of deburring, porosity reduction and lubricant impregnation.
15 . A method of preparing a titanium-based material for powder metallurgy processing, said method comprising:
placing a plurality of precursor powder materials comprising substantially pure titanium, titanium hydride, an alloying material and a boron source material into a titanium-based mixing container;
substantially replacing an ambient atmosphere in said mixing container with an inert fluid;
rotating an agitator at a minimum predetermined speed for a minimum predetermined time until a mixture possessing at least one of the following is achieved: (1) at least a twenty percent reduction in powder size; (2) at least a thirty percent increase in tap density of said mixture; and (3) a substantial removal of an oxide film from said titanium powder; and
sintering said mixture.
16 . The method of claim 15 , wherein said agitator comprises a plurality of titanium-based spheres configured to rotate within said mixing container.
17 . The method of claim 15 , wherein said minimum predetermined speed is approximately 3600 rotations per minute, and said minimum predetermined time is approximately four hours.
18 . A method of making a titanium boride reinforced titanium-based metal matrix composite component, said method comprising:
mixing at least a substantially pure titanium powder with an alloying material and a boron source material such that a substantial majority of any oxide forming on said substantially pure titanium powder is removed therefrom;
compacting said mixture into a shape of said component; and
sintering said compacted mixture such that during said sintering, said boron source material reacts with said substantially pure titanium to produce a reinforcing phase made up of said titanium boride.
19 . The method of claim 18 , further comprising adding titanium hydride to said substantially pure titanium powder, alloying material and boron source material prior to said mixing.
20 . The method of claim 18 , further comprising at least one of forging and annealing said component once said sintering is completed.