Structure and Properties of Kh20N80 Alloy Powders Produced by Impact Sintering at Different Temperatures

Abstract

The compaction, structure, and mechanical properties of Kh20N80 powder samples are studied. Most of the powder particles were 25 μm in size. The powders were compacted by impact sintering in vacuum at 1100, 1150, 1200, 1250, and 1300°C at an impact energy of 1200 J/cm 3 . Isothermal holding at these temperatures lasted for 20 min, vacuum during heating and compaction was maintained at 0.013 Pa, and initial strain rate was 6.5 m/sec. The rectangular bars cut out of cylindrical disks were used to determine the density, electrical resistivity, tensile strength, fracture toughness or fracture work of a notched sample, Brinell hardness, compression strength, and plasticity of the samples in various test conditions. It is shown that the mechanical properties of Kh20N80 samples subjected to impact sintering at 1100–1300°C correspond to those of standard Kh20N80 alloy obtained by conventional melting and forging techniques. In particular, the average tensile strength varies from 630 to 740 MPa and compression strength from 800 to 830 MPa. The plasticity of the samples evaluated from necking changes from 30 to 54% with compaction temperature increasing from 1100 to 1300°C. The average plastic strain energy at break of a notched sample increases from 19.5 to 36.0 J/cm 2 .