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在950~1100℃和0.001~0.01 s~(-1)初始应变速率范围内研究了一种新型难变形Ni-Co-Cr基合金的高温拉伸行为。结果表明:在所研究工艺范围内合金的伸长率可达102%~290%,1080℃以下变形时随温度升高、应变速率降低,伸长率逐渐增加,超过1080℃时伸长率开始显著降低;合金的应变速率敏感指数具有与伸长率相似的变化规律。在低于1000℃拉伸时,试样的断裂方式为穿晶韧性断裂;当超过1050~1080℃时,晶界和相界变形量显著增加,表现出超塑性变形特性,裂纹起源于空洞的聚合或长大。当超过1100℃时,合金组织稳定性差,晶粒发生长大,塑性变差。
The tensile behavior of a new type of hard-deformable Ni-Co-Cr-based alloys at 950-1100 ℃ and 0.001-0.01 s -1 initial strain rate was studied. The results show that the elongation of the alloy can reach 102% ~ 290% within the range of the studied technology. When the temperature is below 1080 ℃, the strain rate decreases and the elongation increases with the increase of temperature. When the temperature exceeds 1080 ℃, the elongation begins Significantly decreased; the strain rate sensitivity index of the alloy has similar variation with the elongation. When the tensile stress is less than 1000 ℃, the fracture mode of the specimen is transgranular ductile fracture. When the temperature exceeds 1050 ~ 1080 ℃, the grain boundary and interfacial dendrites increase remarkably and exhibit superplastic deformation characteristics. The cracks originate from cavities Aggregate or grow up. When the temperature exceeds 1100 ℃, the stability of the alloy structure is poor, the grains grow up and the plasticity deteriorates.