Study on the Microstructure, Electrical and Mechanical Properties of Hot Pressing Cr-50 Mass% Ni Alloys Fabricated by Addition of Various Ratios of Nanosized Ni Powders

Abstract

In this work, nanosized Ni (nNi) powders of 50 nm are mixed with Cr and Ni submicron-powders (600 nm) to fabricate ­Cr-50 mass% Ni alloys by vacuum hot pressing. In order to evaluate the influence of the nanosized Ni powders, different amounts of nanosized Ni powders are added to produce the Cr-(50-x) mass% Ni-x mass% nNi alloys (x = 0, 10, 20 , and 30). The hot pressing was maintained at 1275°C, 48 MPa for 1 h. The microstructure evaluation, mechanical, and electrical properties were performed. The results reveal that mechanical and electrical properties are enhanced when increasing the nNi addition. The Cr-20 mass% ­Ni-30 mass% nNi presents the highest relative density of 96.53% and the electrical conductivity of 2.18×104 Scm–1, moreover, the hardness and transverse rupture strength values increase to 76.1 HRA and 1217 MPa, respectively. Moreover, a more homogeneous microstructure and a decrease in the mean grain size to 3.15 μm are acquired. Significantly, this fabrication procedure (adding 30 mass% nanosized nickel powders) results in the optimal microstructure, electrical and mechanical properties of submicron-structured Cr-(50-x) mass% Ni-x mass% nNi alloys.

Keywords

• electrical conductivity
• hot pressing
• transverse rupture strength
• nanosized nickel powders
• cr-50 mass% ni alloy