添加气膜孔对镍基单晶合金DD6蠕变寿命的影响  

Effects of Cooling Hole Addition on Creep Lifetime of Nickel-based Single Crystal Superalloy DD6

作　　者：盛传德 熊新红[1,2] 朱超 戴彭丹 章桥新[3] SHENG Chuande;XIONG Xinhong;ZHU Chao;DAI Pengdan;ZHANG Qiaoxin(School of Logistics Engineering, Wuhan University of Technology, Wuhan 430063;Engineering Research Center of Port Logistics Technology and Equipment, Ministry of Education, Wuhan University of Technology, Wuhan 430063;School of Mechanical and Electronic Engineering, Wuhan University of Technology, Wuhan 430070)

机构地区：[1]武汉理工大学物流工程学院,武汉430063 [2]武汉理工大学港口物流技术与装备教育部工程研究中心,武汉430063 [3]武汉理工大学机电学院,武汉430070

出　　处：《材料导报》2019年第22期3768-3771,共4页Materials Reports

基　　金：国家自然科学基金(51210008)~~

摘　　要：本研究在外加应力为200 MPa、温度为1 000℃的条件下,对镍基单晶合金DD6带气膜孔试样(飞秒激光环形扫描与旋切扫描相结合加工而成)和不带气膜孔试样进行了蠕变实验。实验结果显示,带气膜孔试样的蠕变寿命显著短于不带气膜孔试样的蠕变寿命。借助扫描电镜和透射电镜对试样蠕变前、后的微观结构进行观测发现:不带气膜孔试样的变形机理为位错在塑性比较好的基体相内(γ相)均匀滑移;而带气膜孔试样由于变形主要集中在孔周围,位错大量增殖交叉,从而在γ/γ′两相界面处产生极大的应力集中,直接将强化相即脆硬相(γ′相)剪切贯穿,导致裂纹快速扩展,合金的蠕变寿命显著缩短。Under a constant applied normal stress of 200 Mpa and a temperature of 1 000 ℃, the creep experiments of two nickel-based single crystal superalloy DD6 samples, with a cooling hole (fabricated by circular scanning and trepanning drilling of Femtosecond Laser) and without cooling hole, were conducted. The experiments showed that the creep lifetime of the DD6 sample with a cooling hole was much shorter than that of the sample without cooling hole. With SEM and TEM observing the microstructure before and after creep, it was found that the deformation in the sample without cooling hole was the evenly spread out slip of the dislocations in the plastic matrix phase (γ phase). While the creep deformation in the sample with a cooling hole was mainly localized around the hole, which led to a large number of dislocation multiplication creating a large microscopic stress concentration at the γ/γ′ interface enough to cut through the precipitates, the brittle and stronger γ′ phase, and thus the crack propagation was then much accelerated due to the loss of resistance, and the creep life was shortened significantly.

关 键 词：镍基单晶高温合金DD6 蠕变寿命 位错 应力集中 

分 类 号：TG146.2[一般工业技术—材料科学与工程]