为了分析铸造和锻造条件下 Ni?42Cu 合金的流变行为和热加工性能，在温度为900~1150°C、应变速率为0.001~1 s?1的条件下对合金进行热变形实验。拉伸实验结果表明，950°C 时铸造和锻造两种合金均出现“热塑性低谷”。因为慢速动态再结晶，铸造合金的热塑性降低更为明显。合金(特别是铸造合金)的热塑性降低、晶界开裂归因于枝晶原子向晶界的偏析。随应变速率的增大，锻造合金的热塑性得到提高，这与高应变速率下动态再结晶分数的增加有关。此结果验证了动态再结晶机理随应变速率而变化。计算得到锻造合金的应变速率敏感性和不稳定参数结果表明，此合金在低温如950~1050°C 和高应变速率(0.1和1 s?1)条件下易发生应变集中。根据拉伸和压缩实验结果，合金获得理想热加工性能的最佳温度为1050~1150°C。
In order to analyze the flow behavior and workability of Ni?42Cu in cast and wrought conditions, hot deformation tests were performed at temperatures and strain rates within the ranges of 900?1150 °C and 0.001?1 s?1, respectively. Tensile tests showed a “hot ductility trough” at 950 °C for both alloys. The drop in hot ductility was more considerable in the cast alloy because of the sluggish dynamic recrystallization. The hot ductility drop and grain boundary cracking, particularly in the cast alloy, were attributed to the segregation of detrimental atoms to the boundaries. It was shown that the hot ductility of the wrought alloy could be improved with increasing strain rate. It was associated with increasing the fraction of dynamic recrystallization at higher strain rates. This finding corroborated the change in the mechanism of dynamic recrystallization with strain rate. The strain rate sensitivity and instability parameters calculated for the wrought alloy showed that the material is prone to strain localization at low temperatures, i.e., 950?1050 °C, and high strain rates of 0.1 and 1 s?1. Based on the tensile and compression tests, the best temperature range for a desirable hot workability was introduced as 1050?1150 °C.
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