Patent ID: 7250134

Claim:
A method for fabricating a steel part having a target bulk composition T of iron (Fe) and N additional basic elements E 1 , E 2 , . . . E N , where N≧1, each present in a respective mass percentage M 1,T , M 2,T , . . . M N,T , and a melting point depressant agent E MPD , present in a mass percentage M MPD,T , comprising the steps of: a. providing a skeleton of interconnected adhered metal particles having a network of interconnected porosities throughout, said particles packed at a packing fraction V PF , said particles having a composition consisting essentially of: i. iron and said N basic elements E 1 , E 2 , . . . E N , each present in a respective mass percentage M 1,K , M 2,K , . . . M N,K ; and ii. said Melting Point Depressant agent E MPD , present in a mass percentage M MPD,K ; b. providing an infiltrant having a composition consisting essentially of: i. iron and said same N elements E 1 , E 2 , . . . E N , each present in a respective mass percentage M 1,I , M 2,I , . . . M N,I ; and ii. said Melting Point Depressant agent E MPD , present in a mass percentage M MPD,I , where M MPD,I >M MPD,T >M MPD,K ; said infiltrant composition being complementary to said skeleton composition, relative to said bulk target composition T; and d. infiltrating said skeleton with said infiltrant, at an infiltration temperature T infil , said infiltration being driven primarily by capillary pressure, said infiltration temperature, said infiltrant composition and said skeleton composition being such that: i. T infil is below a solidus temperature for said skeleton; ii. T infil is above a liquidus temperature for said infiltrant; and iii. at said infiltration temperature, T infil , at chemical equilibrium, a body having said target composition T, has at least about 7 vol % liquid, and is less than about 50 vol % liquid.