Behavior of Мо_xCr_yТа_zSi₂ Solid Solutions during Cyclic Heating in Air

Abstract

High-temperature tests of new heat-resistant and thermal shock-resistant materials based on a solid solution of molybdenum (Мо_xCr_yТа_zSi₂) have been performed under conditions of heating–cooling in air in a cyclic regime in the temperature range 300–1600°С. The tests have shown that compact specimens of solid solutions have high thermal shock resistance. The heat resistance of specimens of the solid solution is much higher than that of MoSi₂ under experimental conditions. It has been established that the heat resistance of the solid solution depends on its composition: the heat resistance of Mo_0,60Cr_0,36Ta_0,04Si₂ is two times higher and the heat resistance of Mo_0,90Cr_0,18Ta_0,02Si₂ is larger by an order of magnitude than that of MoSi₂. With increase in the Cr content up to 18 mol.%, the heat resistance increases, but further increase in its content leads to the degradation of the characteristic because the strength of the protective surface film decreases. The solid solutions based on MoSi₂ can be recommended as heat-resistant and thermal shock-resistant materials for operation in air in a cyclic regime at temperatures up to 1600 °С.