| 摘要: |
| 在钎焊温度1123~1273 K,保温时间120~1500 s参数范围内对TiAl合金与42CrMo钢进行了真空扩散钎焊.用光学显微镜、扫描电镜和能谱分析等方法对界面组织进行了分析,用图像分析软件工具测量了反应层厚度;采用纳米压痕仪和显微硬度仪对TiAl合金/42CrMo钢钎焊接头的两种母材和接头界面反应相进行了硬度测试,对结果进行了对比,为了确定接头的薄弱环节,进行了扫描电镜原位观察下的接头拉伸试验.结果表明,AlCuTi,Ti3Al,AlCu2Ti和TiC的硬度较高,而银的固溶体硬度较低;纳米压痕的硬度结果比显微硬度值略高;扫描电镜下的原位拉伸试验结果表明,Al-Cu-Ti系反应层在受外力作用下容易发生脆性断裂,为接头的薄弱环节. |
| 关键词: TiAl 钎焊 反应相 纳米压痕 |
| DOI： |
| 分类号: |
| 基金项目:国家自然科学基金资助项目(50975062);江西省教育厅资助项目(GJJ13064) |
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| Characteristics of reaction phases and effects of phases on mechanical properties of TiAl/42CrMo steel brazed joint |
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LI Yulong1,2, LV Mingyang1, FENG Jicai2, HE Peng2
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1.Key Lab for Robot & Welding Automation of Jiangxi Province, Mechanical & Electrical Engineering School, Nanchang University, Nanchang 330031, China;2.State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001, China
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| Abstract: |
| TiAl alloy and 42CrMo steel were vacuum brazed at temperature of 1 143-1 213 K for 120 s-1 500 s. The microstructure was analyzed using optical microscope,scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). The thickness of the reaction layers was measured using an analysis software. The hardness of the reaction layers and phases was tested and compared using nano-indenter and traditional microhardness tester. In order to determine the weak phases or layers,the brazed joints were tensile tested with in-situ observation by SEM. The results show that TiC,AlCuTi,Ti3Al and AlCu2Ti phases had higher hardness but the Ag-based solid solution was much softer. The hardness values acquired using the nano-indenter were a little higher than those traditional microhardness tester. The tensile test results revealed that the Al-Cu-Ti ternary layer adjacent to the TiAl substrate was the weakest part. When subjected to tensile load,cracks easily occurred in this zone and resulted in failure. |
| Key words: TiAl brazing reaction phase nano-indentation |
