摘要
采用电阻炉加热自约束热疲劳试验机对激光3D打印Ti60A高温钛合金进行200~2000次的热疲劳试验,对比研究了热疲劳循环次数对合金显微组织特征、显微硬度、裂纹长度和深度等的影响,分析表明:经800次热疲劳循环后裂纹萌生,合金中出现“反常粗化的α相”非均匀组织,这主要是由循环热应力和氧原子间隙固溶的共同作用促进β相更多转变为α相形成的。热疲劳裂纹萌生位置主要在晶界,α/β相界,微孔和“反常粗化的α相”区域。研究结果可为优化高温钛合金的综合力学性能和提高航天器钛合金构件高温服役可靠性提供重要参考。
In this paper,the thermal fatigue tests(700℃55 s+20℃5 s)from 200 to 2000 times were performed using a resistance stove.The crack initition behavior of laser 3D printed Ti60A alloy was investigated as functions of thermal fatigue cycles and microstructural changes.The effect of thermal fatigue cycles on microstructure changes,microhardness and crack length and deepth was studied.The results show that the abnormal coarsenedαand fragmentedβappears in the alloy after 800 thermal fatigue cycles due to the combined effect of thermal stress accumulation and oxygen interstitial solution.Thermal fatigue cracks initiate preferably at grain boundaries,α/βinterfaces,microvoids,and abnormal coarsenedα.The results are important references for optimizing the general mechanical properties of high⁃temperature titanium alloys and improving the service⁃security of titanium alloy parts used in aircraft.
作者
张阿莉
刘锦涛
纪嘉龙
丁凤林
齐瑾
魏延明
Zhang Ali;Liu Jintao;Ji Jialong;Ding Fenglin;Qi Jin;Wei Yanming(Beijing Institute of Control Engineering,Beijing 100094,China)
出处
《西北工业大学学报》
EI
CAS
CSCD
北大核心
2018年第S01期80-85,共6页
Journal of Northwestern Polytechnical University
关键词
激光
3D打印
钛合金
热疲劳
裂纹萌生
laser 3D printing
titanium alloy
thermal fatigue
crack initiation
