The Influence of Constituents and MA Conditions on the Mechanical Properties of Ni3Si Intermetallic Compounds.

Ni3Si intermetallic compounds have an excellent corrosion resistance in sulphuricacid solution. However, production of these compounds was difficult because of poor ductility caused by formation of a very brittle phase. In order to suppress formation of the brittle phase, process conditions involving a mechanical alloying(MA) method have been investigated for the production of Ni3Si intermetallic compounds. First, fine Ni-Si composite powders prepared by the MA method were hot extruded. Then Ni3Si intermetallic compounds were obtained by a particular heat treatment. Influence of the constituents and the MA conditions on mechanical properties of the Ni3Si intermetallic compounds were investigated. As a result, in 13.1 mass%Si- 86.9 mass%Ni materials, tensile strength improved as MA time became longer, although the material had poor ductility. When the Si content was reduced below 13.1 mass%, the tensile strength improved and ductility increased. The critical Si content for achieving of ductility was 12.2 mass%Si.