赵广迪,臧喜民.W对难变形高温合金U720Li热塑性特征和γ′析出行为的影响[J].稀有金属材料与工程,2021,50(8):2867~2875.[Zhao Guangdi,Zang Ximin.Effect of W on the thermal plasticity and γ′ precipitation behavior of hard-deformed superalloy U720Li[J].Rare Metal Materials and Engineering,2021,50(8):2867~2875.]
W对难变形高温合金U720Li热塑性特征和γ′析出行为的影响
投稿时间:2020-08-28  修订日期:2020-09-17
中文关键词:  难变形高温合金    热塑性  γ′析出
基金项目:国家自然科学基金资助(项目号51904146,U1960203)
中文摘要:
      利用真空感应炉制备了三种W含量(1.02 wt.%、0.52 wt.%和0 wt.% W)的难变形高温合金U720Li铸件并对其进行了均匀化处理,重点研究了W对均匀化态U720Li合金热变形行为和开裂特征的影响。结果表明,W含量的减少导致均匀化炉冷态合金在1000 ℃的变形抗力逐渐降低,当W含量减少至0 wt.%时拉伸塑性大幅提高,断裂模式由沿晶断裂转变为沿晶-穿晶混合断裂。随着W含量的降低均匀化炉冷态和空冷态合金晶内的显微硬度均逐渐下降,γ′尺寸明显增大,体积分数逐渐减小。W对变形抗力和热塑性造成影响的主要原因是,W的减少不仅降低了固溶强化程度,还改变了γ′的特征,促进动态再结晶的发生。另外,本文揭示了W主要分布在γ基体中,并据此讨论了W对γ′析出的作用机理。
Effect of W on the thermal plasticity and γ′ precipitation behavior of hard-deformed superalloy U720Li
英文关键词:hard-deformed superalloy  tungsten  thermal plasticity  γ′ precipitation
英文摘要:
      In this work, U720Li castings with different W contents (1.02 wt.%, 0.52 wt.% and 0 wt.%) were prepared by vacuum induction melting and subsequently homogenized. The effect of W on hot deformation behavior and fracture characteristics of as-homogenized U720Li alloy was studied emphatically. The 1000 ℃ tensile test results of homogenized and furnace cooled alloys revealed that with the reduction of W content the deformation resistance decreased gradually, and when the W content was reduced to zero the tensile plasticity was greatly improved and the fracture mode was shifted from intergranular fracture to a mixed-mode of intergranular and transgranular fracture. For both furnace-cooled and air-cooled alloys, with the reduction of W addition the grain-interior microhardness decreased gradually, the size of precipitation strengthening phase γ′ increased and the volume fraction of γ′ decreased markedly. The main reason for the influence of W on deformation resistance and thermal plasticity is that the decrease of W not only reduced the solid solution strengthening, but also modified the characteristic of γ′ which promoting the occurrence of dynamic recrystallization. In addition, the distribution of W in U720Li alloy has been revealed in this paper, i.e., W is mainly enriched in the γ matrix, and the mechanism by which W influencing the precipitation of γ′ was discussed accordingly in the text.
作者单位E-mail
赵广迪 辽宁科技大学 gdzhao12s@alum.imr.ac.cn 
臧喜民 辽宁科技大学  
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