MICROSTRUCTURE AND MECHANICAL PROPERTIES OF AMORPHOUS AND METAMORPHIC ALLOY PRODUCTS FABRICATED BY POWDER INJECTION MOLDING

Abstract

In the present study, a powder injection molding (PIM) process was applied to Cu-based amorphous and Fe-based metamorphic alloys, and microstructure, hardness, and wear resistance of the PIM products were analyzed and compared with those of conventional stainless steel products. Injection-molded Cu-based amorphous powders were not completely sintered even at temperatures just below the melting temperature as all amorphous phases were replaced by crystalline phases. When Fe-based metamorphic powders were injection-molded and then sintered at 1200 degrees C, completely densified products with almost no pores were obtained. They contained 34 vol.% of (Cr,Fe)(2)B borides in the austenite matrix without amorphous phases. Since these (Cr,Fe)2B borides were very hard and thermally stable, hardness, high-temperature hardness, and wear resistance of the Fe-based metamorphic alloy products were two or three times as high as those of conventional stainless steel products. This property improvement presented new possibilities for their application to structural materials or parts requiring excellent mechanical properties.