Features of the surface relief of TiNi alloy in coarse-grained and ultrafine-grained states at room and elevated temperatures

Abstract

The effect of coarse-grained (CG) and ultrafine-grained (UFG) structures processed by equal channel angular pressing on the formation and features of the surface relief during mechanical tensile tests at room and elevated temperatures was studied. The formation of the UFG structure leads to a significant increase in strength, but the ductility decreases. Coarse-grained samples in the quenched state after tensile tests have a developed relief and microcracks. After tensile testing of the annealed CG sample, a similar situation is observed. On samples in the UFG state, no developed relief and cracks were found. The surface of the UFG sample in the annealed state at a temperature of 500 °C shows a very weak relief, but no cracks are observed. Possible reasons of these effects are discussed.