The strength characteristics of layers produced by electrospark alloying of steels with refractory metals

Abstract

1. An investigation was conducted into the strength of layers obtained by electrospark alloying of iron and steel cathodes by refractory metals. 2. It was established that when cathode materials are strengthened by metals that form with them unlimited solid solutions and have low (below 20 °C) temperatures of transition to the brittle condition, the highest values of σad and τsh are found. 3. The stresses in the strengthened layer are tensile and they are lowest in the case of strengthening by metals that form unlimited solid solutions with the cathode material. As a result of the high residual tensile stresses in the surface layer, the fatigue strength of the alloyed samples is lower than in the unstrengthened ones. 4. To reduce residual tensile stresses and, consequently, to increase the fatigue strength of alloyed parts it is desirable to employ a short-circuiting current less than 20 A, a protective interelectrode medium such as argon, strengthening with an anode material that forms with the cathode material an unlimited solid solution, and fine grinding of the alloyed surface, especially by electromechanical means.