DZ125镍基高温合金高温持久断裂后的位错组态

来源期刊：金属学报2011年第1期

论文作者：丁智 张军 王常帅 苏海军 刘林 傅恒志

文章页码：47 - 52

关键词：熔体超温处理； 高温持久寿命； 位错组态； 镍基高温合金

Key words：melt superheating treatment； high temperature stress rupture life； dislocation configuration； Ni-based superalloy

摘    要：研究了熔体超温处理工艺对DZ125镍基高温合金铸态及热处理态高温持久试样位错组态的影响.结果表明:铸态试样的高温持久寿命随熔体超温处理温度的升高而增加.热处理态试样的高温持久寿命随超温处理温度的升高表现为先增加后减少,当超温处理温度为1650℃时,持久寿命达到最大值.随熔体超温处理温度的升高,铸态试样位错密度增大且位错多呈波浪形和不规则网络状分布,热处理态试样中出现规则的多边形位错网,有利于持久性能的提高.位错网中位错的Burgers矢量为a/2〈110〉和a〈100〉.高温持久变形机制为位错的切割或攀移.随超温处理温度的升高,切入γ′相的位错数量减少,并且有位错列和位错对列攀移通过γ′相.

Abstract: The influence of the melt superheating treatment on the dislocation configuration in the as-cast and heat-treated samples of DZ125 Ni-based superalloy after high temperature stress rupture is studied. The results show that with the increase of the melt superheating temperature, the stress rupture life of the as-cast sample is increased and that of the heat-treated sample is first increased and then reduced. When the superheating temperature is 1650℃, the stress rupture life of the heat-treated sample reaches the maximum. With the increase of the melt superheating temperature, the dislocation density is increased and the waved or irregular dislocation networks appear in the as-cast sample, while the regular polygonal dislocation networks appear in the heat-treated sample, which is helpful to elevate the stress rupture property. The Burgers vectors of dislocations in the network are respectively a/2<110> and a<100>. The high temperature stress rupture deformation mechanism is mainly shearing and climbing of dislocation. It is demonstrated that there are few dislocations shearing the γ’ phase and there are dislocation arrays or pairs climbing over the γ’ phase.