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


I. M. Frantsevich Institute for Problems of Materials Science of the NAS of Ukraine, Krzhizhanovsky str., 3, Kyiv, 03142, Ukraine
Powder Metallurgy - Kiev: Frantsevich Institute for Problems of Materials Science NASU, 2015, #07/08


The consolidation, structure, and mechanical properties of Kh20N80 powder samples are studied. Most of the powder particles were 25 µm in size. The powders were consolidated by impact sintering in vacuum at 1100, 1150, 1200, 1250, and 1300 °C at an impact energy of 1200 J/cm3. Isothermal holding at these temperatures lasted for 20 min, vacuum during heating and consolidation 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 measured by contraction at tensile changes from 30 to 54% with consolidation temperature increasing from 1100 to 1300 °C. The average plastic strain energy with failure of a notched sample increases from 19.5 to 36.0 J/cm2.