Using Fe ± 3 . 5%Mo (MSP 3 . 5Mo) prealloyed powders, various steels were manufactured with 0 . 7% carbon addition but different contents of copper and nickel. All the steels were compacted at 700 MPa and sintered in a N 2 ± H 2 atmosphere at 1150³C. After being sintered, the materials were thermochemically treated by means of plasma nitriding and gas nitriding. The mechanical properties evaluated were: tensile and yield strengths, elongation, hardness, microhardness, and wear resistance against two reference materials (steel and alumina). A complete metallographic study was carried out using optical and scanning electron microscopy. Properties of the materials following the two thermochemical treatments were compared, and the relationship of properties to the microstructure was analysed. Nickel and copper improve the mechanical properties in the sintered state and after thermochemical treatment. Plasma nitriding enhances the mechanical properties and wear resistance.MST/4699

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Resumen Partiendo de los aceros inoxidables AISI 316L y 304L a los que se añadió cobre y bronce en diferentes porcentajes hasta el 20 % en peso, se estudia el efecto que la cantidad de aleante y la temperatura de sinterización tienen sobre las propiedades físicas y mecánicas y sobre la microestructura de los aceros inoxidables sinterizados. La aleación con cobre y con bronce aumenta la densidad de los aceros sinterizados para las dos temperaturas de sinterización utilizadas. El cobre y el bronce provocan la aparición de fase líquida (transitoria o permanente) que activa el proceso de sinterización. La resistencia a la tracción del acero inoxidable experimenta un fuerte incremento para los contenidos más elevados de aleante. Además, la resistencia a la tracción alcanza mayores valores para la aleación con bronce que con cobre.Palabras clave: Acero inoxidable. Aleación. Pulvimetalurgia.Copper and bronze influence on sintered austenitic stainless steels properties AbstractThe effect that, on AISI 316L and 304L stainless steels alloyed with copper and bronze in different percentages up to a maximun of 20 % wt, produce both the alloying contení and the sintering temperature over physical and mechanical properties and over the microstructure of sintered stainless steels are studied. Alloying with copper and bronze improves the density of sintered steels at the two sintering temperatures used. Copper and bronze promote liquid phase sintering (transitory or permanent), that activates sintering process. Tensile strength of stainless steel is highly improved for higher alloying contents. Moreover, tensile strength presents greater valúes alloying with bronze than with copper.

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