材料期刊网

高温形变热处理使一种铁镍基合金的室温和高温屈服强度、抗张强度、塑性和室温冲击韧性大幅度提高,且经1100℃形变热处理的合金于650℃的持久性能亦不低于正常热处理的合金。本文着重研究了形变温度对组织和力学性能的影响,指出不同温度下的形变热处理具有不同的强化机理,它们分别为晶粒细化、晶内交叉滑移、位错亚结构、锯齿状晶界和晶界析出物的增加。

An iron-nickel base superalloy (Fe-35Ni-15Cr-2.7Al-2.5Ti-2W-2Mo) was subjected to high temperature thermomechanical treatment (HTMT) at 900, 1000 and 1100℃. The mechanical properties were evaluated. Results indicate that substantial improvement in tensile and yield strength, ductility and notch toughness can be accomplished by HTMT. Under testing temperature of 650℃, the stressrupture life of 1100℃ thermomechanically treated superalloy is not lower even than that after conventional normal heat treatment. In particular, the influence of deformation temperature on the structure and the mechanical properties of the superalloy was studied by both optical and electron microscopy. It is clarified that the strengthening mechanism caused by HTMT under various temperatures may be grain refinement, cross slip, sawtoothed grain boundaries, precipitation along grain boundaries and dislocation substructure formation.