Ni_3Al(Z)合金室温拉伸性能及Zr韧化机制的探讨

Tensile Properties of Ni_3Al(Zr) Alloy at Room Temperature and the Mechanism of Ductility through Zr Improving

热处理温度显著影响Ni3Al(Zr)合金的显微组织和室温力学性能。本实验采用SEM,TEM,AES等手段对轧制处理后的试样进行了研究。随着热处理温度升高,再结晶体积百分数增加,再结晶晶粒尺寸增大,室温拉伸强度降低。但室温拉伸塑性随热处理温度升高而增加,在850℃热处理时达到最大值,然后随热处理温度升高而显著降低。俄歇能谱(AES)研究表明Zr在850℃热处理时的晶界偏聚量明显高于1100℃热处理时的偏聚量,说明Zr在室温的塑化作用与其在晶界的分布有关。

Microstructure and tensile properties of the Ni3Al(Zr) are evidently influenced by the heat-treatment temperatures. The rolling specimens were analyzed by SEM, TEM, and AES. With the increase of heat-treatment temperature, both the fraction of recrystallized zone and grain size increase, and the tensile strength decrease. The ductility of Ni-22.4at%Al-0.6at%Zr alloy rises with increasing heat-treatment temperature, which is the highest when treated at 850degreesC, then drops obviously. The study by Auger electron spectroscopy indicates that Zr segregate on the grain boundary of Ni3Al, and the amount of Zr in specimen treated at 850degreesC is more than that at 1 100degreesC. This demonstrates the amount of Zr segregated on the grain boundary affects the ductility of Zr-doped Ni3Al alloy.