金属热处理 ›› 2020, Vol. 45 ›› Issue (1): 234-238.DOI: 10.13251/j.issn.0254-6051.2020.01.045

• 测试与分析 • 上一篇    下一篇

7A09铝合金模锻连杆件的开裂分析

刘艳梅1, 赵美兰2, 冯辉3, 白亚茹1, 李妍1, 王铁钢1   

  1. 1. 天津职业技术师范大学 天津市高速切削与精密加工重点实验室, 天津 300222;
    2. 天津重型装备工程研究有限公司, 天津 300222;
    3. 中国科学院 金属研究所, 辽宁 沈阳 110016
  • 收稿日期:2019-06-20 出版日期:2020-01-25 发布日期:2020-04-03
  • 通讯作者: 王铁钢,教授,博士,主要从事硬质薄膜与刀具涂层技术研究,E-mail:sytgwang@163.com
  • 作者简介:刘艳梅(1976—),女,工程师,硕士,主要从事材料分析方法、失效分析、变形高温合金组织和性能的研究,E-mail:13502158936@163.com。
  • 基金资助:
    国家自然科学基金(51301181);天津市科技军民融合重大专项(18ZXJMTG00050);天津市高等学校创新团队培养计划(TD13-5096);天津职业技术师范大学校级科研项目(KJ1812,KJ1911);天津职业技术师范大学大学生创新创业训练项目(201710066058)

Failure analysis on cracking of die-forged connecting rod of 7A09 alloy

Liu Yanmei1, Zhao Meilan2, Feng Hui3, Bai Yaru1, Li Yan1, Wang Tiegang1   

  1. 1. Tianjin Key Laboratory of High Speed Cutting and Precision Processing, Tianjin University of Technology and Education, Tianjin 300222, China;
    2. Tianjin Heavy Equipment Engineering Research Co., Ltd., Tianjin 300222, China;
    3. Institute of Metal Research, Chinese Academy of Sciences, Shenyang Liaoning 110016, China
  • Received:2019-06-20 Online:2020-01-25 Published:2020-04-03

摘要: 通过断口形貌、显微组织、硬度以及化学成分等方法研究了7A09铝合金模锻连杆件开裂的原因。结果表明:裂纹主要起源于样品表面,并且从表面向试样内部沿晶界扩展;开裂试样的显微组织有晶界宽化、复熔共晶组织的现象,大致判定为过烧组织。主要原因是热处理过程中的温度失控导致7A09铝合金连杆件失效断裂,从而引起产品硬度下降,晶界强度下降,并提出了相关的改进措施。

关键词: 7A09铝合金, 开裂, 原因分析, 过烧

Abstract: The causes of cracking failure of die-forged connecting rod of 7A09 alloy were studied by means of fracture morphologies, macrostructure, microstructure, hardness, chemical composition. The results show that the cracks are originated from the specimens surface, and gradually extended to the interior along the grain boundaries. Simultaneously, there are grain boundary broadening and remelting eutectic microstructure in the cracked specimens, which roughly can be judged the burnt microstructure.It is concluded that the overburning owing to temperature being out control during heat treatment is the main cause of cracking of die-forged connecting rod of 7A09 alloy, and results in the decrease of hardness and grain boundary strength. And the relevant improvement measures are put forward.

Key words: 7A09 aluminum alloy, cracking, failure analysis, over-burning

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