摘要
通过蠕变性能测试、组织形貌观察,研究了定向凝固镍基高温合金热处理后组织形貌及其在760℃、700 MPa条件下蠕变不同时间的损伤机制。结果表明,合金热处理后,枝晶间和枝晶干区域的γ′相尺寸差异较大,粗大的γ′相和细小的γ′相分别存在于枝晶间和枝晶干区域。在760℃、700 MPa条件下合金蠕变断裂后立方γ′相并不形成筏状组织,并且越接近断口区域的γ′相扭曲越剧烈,这是由于在蠕变过程中试样断口区域发生了较大程度颈缩所致。蠕变后期,合金中裂纹首先在晶界和未完全消除的共晶组织处萌生与扩展,其中,沿与应力轴成45°的晶界承受较大剪切应力,因此发生蠕变损伤几率较大。
The morphologies of directionally solidified nickel-based superalloy after heat treatment and damage mechanism of the alloy at 760 ℃ and 700 MPa for different creep duration were investigated by creep property test and microstructure observation. The results reveal that after heat treatment, the sizes of γ′ phases between interdendritic region and dendrite arms are greatly different, where the coarse and fine γ′ phase exist in interdendritic and dendrite arm region, respectively. The cubic γ′ phase does not form raft structure after the alloy creep rupture at 760 ℃ and 700 MPa, and the closer to the fracture area, the more severe γ′phase distortion, which is attributed to the necking to a greater extent at the fracture during the creep. In the later stage, cracks in the alloy are firstly initiated and propagated at grain boundary and eutectic structure that is not eliminated, where the grain boundary at a 45 angle to the stress axis suffers the higher shear stress, enhancing creep damage probability.
作者
田宁
赵国旗
潘玲
张顺科
杨娜
张卫华
Tian Ning;Zhao Guoqi;Pan Ling;Zhang Shunke;Yang Na;Zhang Weihua(School of Mechanical Engineering,Guizhou University of Engineering Science)
出处
《特种铸造及有色合金》
CAS
北大核心
2022年第7期810-813,共4页
Special Casting & Nonferrous Alloys
基金
贵州省科学技术基金资助项目(20201Y198)
毕节市科学技术项目(20192)
贵州省科技计划资助项目(20192843)
贵州省教育厅青年科技人才成长计划资助项目([2022]121,[2022]125,[2022]129,[2022]134)
关键词
定向凝固镍基合金
蠕变
晶界
裂纹萌生与扩展
Directionally Solidified Nickel-based Superalloy
Creep
Grain Boundary
Crack Initiation and Propagation
