Process for forming porous metal-second phase composites
AssigneeMartin Marietta Corporation
InventorsWilliam C. Moshier, John M. Brupbacher, Leontios Christodoulou, Dennis C. Nagle
Life of this patent
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Abstract
A method is taught for the in-situ precipitation of second phase materials, such as ceramic or intermetallic particles, in a substantial volume fraction of solvent metal matrix. The invention involves the propagating reaction of the second phase-forming constituents in a solvent metal medium to provide a porous composite of finely-dispersed second phase particles in the metal matrix. Exemplary materials include titanium carbide or titanium diboride in an aluminum matrix.
Claims67
A method for the production of porous metal-second phase composite material, the method comprising precipitating at least one second phase material in a solvent metal by locally igniting a mixture comprising reactive second phase forming constituents and at least about 20 volume percent of a substantially nonreactive solvent metal in which the second phase-forming constituents are move soluble than the second phase material, substantially at or below atmospheric pressure and at a temperature at which sufficient diffusion of the reactive second phase forming constituents into the substantially nonreactive solvent metal occurs to cause a substantially isothermal second phase forming reaction of the constituents to thereby precipitant second phase particles in the solvent metal so as to produce a solid composite material having a porosity of at least 10 percent comprising finely divided second phase particles in the metal matrix.
The method as set forth in claim, wherein the second phase particles are substantially encapsulated by solvent matrix metal.
A method for dispersion of a second phase in a metal, metal alloy, or intermetallic matrix, the method comprising steps of:
- (a) preparing a mixture of reactive second phase-forming constituents and at least about 20 volume percent of a nonreactive solvent metal in which the second phase-forming constituents are moe soluble that the second phase;
- (b) locally heating the mixture substantially at or below atmospheric pressure to a reaction initiation temperature approximating the melting point of the solvent metal to initiate a substantially isothermal reaction;
- (c) permitting the reaction wave front to propagate and to further heat the mixture, consuming the second phase-forming constituents, forming a distribution of second phase particles in the matrix;
- and
- (d) recovering a solid metal-second phase composite material having a porosity of at least 10 percent.
A method for the production of porous metal-second phase composite materials, the method comprising precipitating at least one second phase material in solvent matrix by locally igniting a mixture of reactive second phase-forming constituents and at lest about 20 volume percent of a substantially nonreactive solvent metal in which the second phase-forming constituents are more soluble than the second phase, substantially at or below atmospheric pressure and at a temperature at which sufficient diffusion of the constituents into the solvent metal occurs, to cause propagation of a substantially isothermal reaction of the reactive second phase-forming constituents to increase the temperature to a temperature exceeding the melting temperature of the solvent metal, to precipitate the second phase in the solvent metal, thereby forming a metal-second phase composite material having a porosity of at least 10 percent.
A method for providing a second phase in a metallic matrix, the method comprising steps of:
- (a) preparing a mixture of reactive second phase-forming constituents and at least about 20 volume percent of nonreactive solvent metal in which the second phase-forming constituents are more soluble than the second phase;
- (b) locally heating the mixture substantially at or below atmospheric pressure to a reaction initiation temperature approximating the melting point of the solvent metal to initiate a substantially isothermal reaction wave front;
- (c) permitting the exothermic reaction to further heat the mixture and to propagate, forming a uniform distribution of second phase particles in a metallic matrix;
- and
- (d) recovering a metal-second phase composite material having a porosity of at least 10 percent.
A method for dispersion of second phase dispersoids in a metallic matrix, the method comprising forming a reaction mixture of reactive second phase-forming constituents in the presence of a substantial volume fraction of at least two metals, at least one of which acts as a solvent metal in which the second phase-forming constituents are more soluble than the second phase dispersoids, holding the mixture substantially at or below atmospheric pressure, raising the temperature of the reaction mixture locally to a temperature at which sufficient diffusion of the second phase-forming constituents into the lowest melting solvent metal occurs to initiate a substantially isothermal reaction of the constituents, whereby the exothermic heat of reaction of the constituents causes the temperature of the reaction mixture to locally exceed the melting point of the highest melting metal, permitting propagation of the reaction, and dispersion of the second phase dispersoid in an alloy to thereby form a solid metal-second phase composite material having a porosity of at least 10 percent.
A method for dispersion of second phase dispersoids in a metal matrix, the method comprising forming a reaction mixture of reaction second phase-forming constituents in the presence of at least about 20 volume percent of a mixture of at least two metals, at least one of which acts as a solvent metal in which the second phase-forming constituents are more soluble than the second phase dispersoids, holding the mixture substantially at or below atmospheric pressure, raising the temperature of the reaction mixture locally to a temperature at which sufficient diffusion of the second phase-forming constituents into the lowest melting solvent metal occurs to initiate a substantially isothermal reaction of the constituents, whereby the exothermic heat of reaction of the constituents causes the temperature of the reaction mixture to exceed the melting point of the lowest melting point solvent metal, permitting propagation of the reaction and dispersion of the second phase dispersoids in a mixed metal matrix to thereby form a solid metal-second phase composite material having a porosity of at least 10 percent.
A method for dispersion of at least one intermetallic material in a metallic matrix, comprising steps of:
- (a) preparing a mixture of reactive intermetallic-forming constituents and a substantial volume fraction of nonreactive solvent metal, metal alloy, or intermetallic in which the intermetallic-forming constituents are more soluble than the intermetallic material;
- (b) locally heating the mixture substantially at or below atmospheric pressure to a reaction initiation temperature approximating the melting point of the solvent metal, metal alloy or intermetallic;
- (c) permitting the resultant exothermic reaction to raise the temperature of the mixture to a temperature exceeding the melting point of the solvent metal, and to propagate, as a substantially isothermal wave front consuming the intermetallic-forming constituents;
- and
- (d) recovering a solid metal-intermetallic composite material having a porosity of at least 10 percent.
A method for dispersion of at least one ceramic material in a metallic matrix, comprising steps of:
- (a) preparing a mixture of reactive ceramic-forming constituents and t least about 20 volume percent of nonreactive solvent metal in which the ceramic-forming constituents are more soluble than the ceramic material;
- (b) locally heating the mixture substantially at or below atmospheric pressure to a reaction initiation temperature approximating the melting point of the solvent metal;
- (c) permitting the resultant exothermic reaction to raise the temperature of the mixture to a temperature exceeding the melting point of the solvent metal, and to propagate, as a substantially isothermal wave front consuming the ceramic-forming constituents;
- and
- (d) recovering a slid metal-ceramic composite material having a porosity of at least 10 percent.
A method for dispersing dispersoid particles of an intermetallic material and a ceramic material in a metal matrix, the method comprising steps of:
- (a) preparing a mixture of reactive intermetallic and ceramic-forming constituents and at least about 20 volume percent of nonreactive solvent metal in which the intermetallic-forming constituents and the ceramic-forming constituents are more soluble than the intermetallic or the ceramic material, respectively;
- (b) locally heating the mixture substantially at or below atmospheric pressure to a reaction initiation temperature approximating the melting point of the solvent metal;
- (c) initiating an exothermic reaction to raise the temperature of the mixture to a temperature exceeding the melting point of the solvent metal, and to propagate, as a substantially isothermal wave front consuming the intermetallic-forming constituents and ceramic-forming constituents;
- and
- (d) recovering a solid composite material having a porosity of at least 10 percent.
A method for the production of porous metal-second phase composite material, the method comprising forming at least one second phase material in nonreactive metal by locally igniting a mixture comprising reactive second phase-forming constituents in the presence of at least about 20 volume percent of a substantially nonreactive metal substantially at or below atmospheric pressure and at a temperature that causes a substantially isothermal propagating second phase-forming reaction of the constituents to propagate as an isothermal wave front, to thereby form second phase particles in the metal and recovering a solid composite material having a porosity of at least 10 percent.
Dependencies are inferred from the claim text.