Effect of aging on the temperature dependence of the mechanical properties of Mo?C?Zr alloys

Abstract

1. The temperature dependence of the mechanical properties is correlated with structural transformations that occur during high-temperature testing. The extremal properties (highest strength and lowest ductility, and also lowest resistivity) depend on aging processes (precipitation hardening). 2. Precipitation hardening occurs in Mo\t-C alloys when elements of group IVA are added, particularly zirconium, the effect increasing with the extent of alloying with zirconium and carbon (in the stoichiometric ratio of ZrC-1:1). Precipitation hardening is greatest for alloy TsM-5 in the quenched (recrystallized) condition at 1400° (σb=47 kg/mm2), and is lacking in the wrought condition. 3. Heat treatment (aging) before the tests of Mo\t-C\t-Zr alloys reduces the effect of precipitation hardening characteristic of the recrystallized metal, and at the optimal aging temperature eliminates it completely. 4. The aging process, which is responsible for the temperature dependence of the mechanical properties, occurs in the Mo\t-C\t-Zr and Mo\t-C alloys at 900\2-1800\dg, with a peak of 1600\dg. With the application of stress, i.e., in mechanical tests, the temperature of the maximum precipitation hardening decreases to 1400\dg.