• CN:11-2187/TH
  • ISSN:0577-6686

机械工程学报 ›› 2020, Vol. 56 ›› Issue (16): 54-60.doi: 10.3901/JME.2020.16.054

• 材料科学与工程 • 上一篇    下一篇

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氢致TA10钛合金焊接接头断裂韧度演变研究

刘全明1,2, 龙伟民1, 傅莉2, 张朝晖3, 张雷1, 宋晓国4   

  1. 1. 郑州机械研究所有限公司新型钎焊材料与技术国家重点实验室 郑州 450001;
    2. 西北工业大学凝固技术国家重点实验室 西安 710072;
    3. 西安建筑科技大学冶金工程学院 西安 710055;
    4. 哈尔滨工业大学先进焊接与连接国家重点实验室 哈尔滨 150001
  • 收稿日期:2020-03-12 修回日期:2020-04-22 出版日期:2020-08-20 发布日期:2020-10-19
  • 通讯作者: 龙伟民(通信作者),男,1966年出生,研究员,博士研究生导师。主要研究方向为钎焊材料、钎焊工艺与设备、钎涂熔敷技术、焊接结构失效分析。E-mail:brazelong@163.com
  • 作者简介:刘全明,男,1988年出生,博士后。主要研究方向为焊接结构失效分析、钛基钎料研发及应用。E-mail:liuquanming1988@126.com
  • 基金资助:
    国家自然科学基金(U1904197)和河南省科技创新人才计划(204200510031)资助项目。

Fracture Toughness Evolution Induced by Hydrogen of TA10 Titanium Alloy Welded Joints

LIU Quanming1,2, LONG Weimin1, FU Li2, ZHANG Zhaohui3, ZHANG Lei1, SONG Xiaoguo4   

  1. 1. State Key Laboratory of Advanced Brazing Filler Metals and Technology, Zhengzhou Research Institute of Mechanical Engineering Co., Ltd., Zhengzhou 450001;
    2. State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072;
    3. School of Metallurgical Engineering, Xi'an University of Architecture and Technology, Xi'an 710055;
    4. State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001
  • Received:2020-03-12 Revised:2020-04-22 Online:2020-08-20 Published:2020-10-19

摘要: 钛合金焊接件在氢环境中服役面临着氢脆断裂风险,断裂韧度对钛合金损伤容限设计至关重要。研究充氢量对钛合金焊接接头断裂韧度、断口形貌和断裂方式的影响,揭示了固溶氢、氢化物导致焊接接头断裂韧度演变的微观机理。充氢0~0.21wt.% CT试样断裂韧度KQ值由39.6 MPa·m1/2减小到22.1 MPa·m1/2,扩展区断口形貌由大量韧窝+局部少量脆性断裂转为脆性断裂,氢致断裂韧度损失和脆性断裂加剧。应力诱导氢扩散使固溶氢局部富集形成富氢气团,气团存在内压剪切分量使产生局部塑性变形所需外应力下降,焊接接头表观屈服应力下降,促进微裂纹在低KI下孕育。位错运动无法直接切过大尺寸氢化物,位错塞积在氢化物界面处,致局部应力集中,微裂纹在氢化物界面处孕育;同时氢化物为软基体金属中的一种脆性相,应力集中致其产生高应变,氢化物自身断裂,微裂纹在氢化物内部孕育;固溶氢、氢化物均致焊接接头加速开裂。

关键词: 钛合金, 充氢焊接接头, 断裂韧度, 断口形貌, 演变机理

Abstract: Titanium alloy weldments in hydrogen environment are facing with the risk of hydrogen embrittlement, and the fracture toughness is very important for the damage tolerance design of titanium alloy. The effects of hydrogen content on fracture toughness, fracture morphology and fracture mode of titanium alloy welded joints were investigated. Micro-mechanisms of fracture toughness evolution induced by solid solution hydrogen and the hydride for welded joints were revealed. Fracture toughness KQ values of the hydrogenated 0-0.21wt.% CT specimens were decreased from 39.6 MPa· m1/2 to 22.1 MPa·m1/2, the fracture morphology of expansion zone was changed from a large number of dimples + a small amount of local brittle fracture to brittle intergranular fracture, and fracture toughness loss and brittle fracture induced by hydrogen for welded joints were increased. Hydrogen rich air masses were produced by local enrichment of solid solution hydrogen induced by stress-induced hydrogen diffusion. The existence of internal pressure shear component in hydrogen rich air masses resulted in the decrease of external stress required for local plastic deformation, the decrease of apparent yield stress and the promotion of microcracks inoculation at a lower KI level. The dislocation movement could not directly cut the large size of the hydride, and the dislocation plug was generated at the hydride interface, which caused local stress concentration, and the microcracks were incubated at the hydride interface. Besides, the hydride was a brittle phase in the soft matrix metal, which caused high strain due to stress concentration, the hydride itself broke, and the microcracks were incubated inside the hydride. The accelerated cracking of welded joints was caused by solid solution hydrogen and the hydride at once.

Key words: titanium alloy, hydrogenated welded joint, fracture toughness, fracture morphology, evolution mechanism

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