许佳玉,丁雨田,胡勇,高钰璧,王浩,张东.选区激光熔化成形Inconel 738合金裂纹形成机理及各向异性[J].稀有金属材料与工程,2020,49(8):2791~2799.[Xu Jiayu,Ding Yutian,Hu Yong,Gao Yubi,Wang Hao,Zhang Dong.Crack Forming Mechanism and Anisotropy of Inconel 738 Alloy by Selective Laser Melting[J].Rare Metal Materials and Engineering,2020,49(8):2791~2799.]
选区激光熔化成形Inconel 738合金裂纹形成机理及各向异性
投稿时间:2019-07-12  修订日期:2019-09-12
中文关键词:  选区激光熔化  Inconel 738合金  裂纹形成机理  各向异性  力学性能
基金项目:甘肃省科技重大专项项目(项目号No. 17ZD2GC001)
中文摘要:
      采用SEM、EBSD、DSC、XRD和万能拉伸试验机等手段,研究了SLM成形过程中Inconel 738合金裂纹形成机理、组织各向异性以及对力学性能的影响。研究表明,Inconel 738合金在SLM成形过程中奥氏体 相中主要析出 相和MC型碳化物,其凝固过程为L→ → +MC→ + +MC;低熔点 + 共晶组织经再次受热液化形成裂纹源,在残余拉应力的作用下扩展形成微裂纹;同时,微裂纹周围的残余应力均匀分布,微裂纹起始附近的晶粒取向差高于未产生微裂纹的位置;此外,XY面上的微裂纹方向垂直于激光扫描方向,XZ面上的微裂纹方向平行于Z轴;SLM成形Inconel 738合金的择优取向与最大温度梯度有关,在XY和XZ面上晶体均表现出强<100>取向;沿XY和XZ方向的SLM成形试样力学性能均高于精铸试样,且XZ方向的强度高于XY方向,而延伸率小于XY方向。
Crack Forming Mechanism and Anisotropy of Inconel 738 Alloy by Selective Laser Melting
英文关键词:selective laser melting, Inconel 738 alloy, crack forming mechanism, anisotropy, mechanical property
英文摘要:
      Inconel 738 alloy is a precipitation strengthened nickel-base superalloy mainly used in today’s heavy-duty gas turbines for hot gas path components such as blades, vanes and heat shields due to its possesses an exceptional combination of high-temperature strength and oxidation resistance. However, the high Al and Ti contents are highly hot cracking susceptibility during selective laser melting (SLM) forming, easily formed the microcracks, leading to the result in premature failure of the alloy during service, causing major accidents. In this work, the crack formation mechanism, microstructure anisotropy and their effect on mechanical property by SLM forming was investigated by means of SEM, EBSD, DSC, XRD and Universal Tensile Testing Machine. The results show that austenite in Inconel 738 alloy mainly precipitates phase and MC carbide during SLM forming, where the solidification process is L→ → +MC→ + +MC. The low melting point eutectic structure liquefies due to reheat to form crack source, and microcracks are formed under residual tensile stress. Meanwhile, the residual stress around the microcrack distributes uniformly, and the grain misorientation near the initiation of microcrack is higher than that without microcrack zone. In addition, the direction of microcrack on XY plane is perpendicular to the direction of laser scanning, and the direction of microcrack on XZ plane is parallel to Z axis. The preferred orientation of Inconel 738 alloy formed by SLM is related to the maximum temperature gradient. The mechanical properties of SLM formed specimens along XY and XZ directions are higher than those of precision casting specimens, and the strength in XZ direction is higher than that in XY direction, while the elongation in XZ direction is lower than that in XY direction.
作者单位E-mail
许佳玉 兰州理工大学 省部共建有色金属先进加工与再利用国家重点实验室 121213834@qq.com 
丁雨田 兰州理工大学 省部共建有色金属先进加工与再利用国家重点实验室 dingyt@lut.edu.cn 
胡勇 兰州理工大学 省部共建有色金属先进加工与再利用国家重点实验室  
高钰璧 兰州理工大学 省部共建有色金属先进加工与再利用国家重点实验室  
王浩 兰州理工大学 省部共建有色金属先进加工与再利用国家重点实验室  
张东 金川集团股份有限公司镍钴资源综合利用国家重点实验室  
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