Method of modifying the properties of a metal matrix composite body

A method of forming a metal matrix composite body, comprising:

• forming a permeable mass comprising silicon nitride and a carbon source;
• spontaneously infiltrating molten matrix metal into at least a portion of said permeable mass to form an at least partially infiltrated mass comprising said silicon nitride and said carbon source embedded by said matrix metal;
• heating said at least partially infiltrated mass to a temperature which is higher than the temperature at which said permeable mass was at least partially spontaneously infiltrated;
• reacting said matrix metal with said silicon nitride and said carbon source to form at least one reaction product in at least a portion of said at least partially infiltrated mass;
• maintaining said higher temperature for a time sufficient to permit at least a majority of said reaction to occur at said higher temperature;
• and
• cooling said at least partially infiltrated mass.

A method of forming a metal matrix composite body, comprising:

• forming a permeable mass of at least one material selected from the group consisting of a filler material and a preform;
• mixing at least one second material into at least a portion of said permeable mass;
• spontaneously infiltrating molten matrix metal into said permeable mass to form a metal matrix composite body in at least a portion of said permeable mass;
• thereafter heating said spontaneously infiltrated mass to a temperature higher than that temperature at which said permeable mass was spontaneously infiltrated;
• forming at least one reaction product in at least a portion of said spontaneously infiltrated mass;
• and
• cooling said spontaneously infiltrated mass, at least a portion of which has been modified by said reaction product.

A method of forming a metal matrix composite body, comprising:

• providing a permeable mass comprising at least one filler material and at least one second material;
• infiltrating a molten matrix metal into at least a portion of said permeable mass;
• thereafter heating said at least partially infiltrated mass to a temperature higher than the temperature at which said molten matrix metal at least partially infiltrated said permeable mass;
• maintaining said higher temperature for a time sufficient to permit at least some reaction of said at least one second material with at least one member selected from the group consisting of said filler material and said matrix metal;
• and
• cooling said at least partially infiltrated mass.

A method for forming a metal matrix composite body, comprising:

• providing a permeable mass comprising at least one filler material and at least one precursor to a second material;
• infiltrating a molten matrix metal into at least a portion of said permeable mass;
• thereafter heating said at least partially infiltrated mass to a temperature higher than the temperature at which said molten matrix metal at least partially infiltrated said permeable mass;
• maintaining said higher temperature for a time sufficient to form in at least a portion of said at least partially infiltrated mass at least one reaction product of at least one member selected from the group consisting of said filler material and said matrix metal;
• and
• cooling said at least partially infiltrated mass.