Method for forming a metal matrix composite body by an outside-in spontaneous infiltration process, and products produced thereby

A method for making a metal matrix composite, comprising:

• providing a substantially non-reactive filler comprising aluminum oxide, said filler including a cavity portion therein;
• communicating a localized infiltrating atmosphere comprising nitrogen, said infiltrating atmosphere having a composition different from the composition of the atmosphere outside said cavity with at least a portion of said cavity in said filler;
• and
• spontaneously infiltrating at least a portion of the filler with molten matrix metal comprising aluminum.

A continual processing method of making metal matrix composites comprising:

• (a) providing at least one substantially non-reactive preform, said preform including a cavity portion therein;
• (b) communicating a localized infiltrating atmosphere, said infiltrating atmosphere having a composition different from the atmosphere outside said cavity with at least a portion of said at least one cavity in said preform;
• (c) contacting at least a portion of an outside portion of said at least one preform with a pool of molten matrix metal;
• and
• (d) spontaneously infiltrating molten matrix metal into said at least one preform towards said cavity;
• (e) removing said spontaneously infiltrated preform from contact with said matrix metal;
• and
• (f) continually contacting additional preforms with said pool of molten matrix metal and spontaneously infiltrating molten matrix metal into said preforms to continuously form a plurality of said metal matrix composites as described in steps (a)-(e).