Ye Xianjue, Yang Biaobiao, Liu Jiantao, Li Yunping
State Key Lab for Powder Metallurgy, Central South University, Changsha 410083, China.
IMDEA Materials Institute, C/Eric Kandel 2, Getafe, 28906 Madrid, Spain.
Materials (Basel). 2022 Jun 27;15(13):4524. doi: 10.3390/ma15134524.
In this work, the quantification of key microstructural features like γ' size morphology distribution, grain size, and localized stress distribution, especially near a fracture, were coupled with mechanical properties under various temperatures in Ni-base powder metallurgy superalloys subjected to sub-solvus or super-solvus heat treatments. Compared to super-solvus heat-treated alloy, sub-solvus heat-treated superalloy with a finer grain size exhibited higher ductility/strength at 550 °C, whilst adverse trend was observed at higher temperatures (750 and 830 °C). Besides, for both alloys, the strength and ductility decreased with the decrease in strain rate, resulting from oxidation behavior. Larger grain size or less grain boundary density can facilitate the retardation of oxidation behavior and weaken the propensity of early failure at higher temperatures.
在这项工作中，镍基粉末冶金高温合金在亚固溶或超固溶热处理后，关键微观结构特征（如γ'尺寸形态分布、晶粒尺寸和局部应力分布，尤其是在断裂附近）的量化与不同温度下的力学性能相关联。与超固溶热处理合金相比，晶粒尺寸更细的亚固溶热处理高温合金在550°C时表现出更高的延展性/强度，而在较高温度（750和830°C）下则观察到相反的趋势。此外，对于这两种合金，强度和延展性都随着应变速率的降低而降低，这是由氧化行为导致的。更大的晶粒尺寸或更低的晶界密度可以促进氧化行为的延缓，并减弱在较高温度下早期失效的倾向。
