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周利, 赵洪运, 舒凤远, 冯吉才. AlN陶瓷表面单道激光熔覆铜应力应变数值分析[J]. 焊接学报, 2014, 35(9): 57-60.
引用本文: 周利, 赵洪运, 舒凤远, 冯吉才. AlN陶瓷表面单道激光熔覆铜应力应变数值分析[J]. 焊接学报, 2014, 35(9): 57-60.
ZHOU Li, ZHAO Hongyun, SHU Fengyuan, FENG Jicai. Numerical simulation of stress and strain during single-pass laser cladding copper on AlN base plate[J]. TRANSACTIONS OF THE CHINA WELDING INSTITUTION, 2014, 35(9): 57-60.
Citation: ZHOU Li, ZHAO Hongyun, SHU Fengyuan, FENG Jicai. Numerical simulation of stress and strain during single-pass laser cladding copper on AlN base plate[J]. TRANSACTIONS OF THE CHINA WELDING INSTITUTION, 2014, 35(9): 57-60.

AlN陶瓷表面单道激光熔覆铜应力应变数值分析

Numerical simulation of stress and strain during single-pass laser cladding copper on AlN base plate

  • 摘要: 激光熔敷过程中保护气体对工件的散热作用不可忽略,根据简化二维流体模型将散热问题转化为流体力学问题并将对流换热转化为导热,针对保护气体对工件的散热形式展开探讨并对散热效果进行了定量化表征,发现对流换热系数为热导率的数百倍.将保护气体的散热计算结果引入AlN陶瓷表面单道激光熔覆铜应力与应变计算过程中,根据第一和第三强度理论,发现熔覆过程中裂纹产生形式主要包括3种,分别为铜覆层与AlN陶瓷基体结合面撕裂、AlN陶瓷上表面拉裂和垂直于熔覆方向的铜熔覆层横向裂纹,分析其产生机理并据此提出优化工艺参数的指导原则.

     

    Abstract: Cooling effect of shielding gas should not be neglected during laser cladding process. The fluid model was simplified by transforming thermal and convection problems into hydromechanics and conduction problems, respectively. Cooling type of shielding gas was investigated and the heat dissipation was quantitatively characterized. It was found that convection coefficient was several hundreds times of conduction coefficient.The evaluation results were adopted for calculation of stress and strain of copper powder and AlN matrix exposed to single-pass laser cladding. According to the first and third strength theory, three kinds of cracks were obviously found, including tear cracks in the interface, pull cracks on the upper surface of the base metal and transverse cracks in the cladding layer perpendicular to laser scanning direction. The forming mechanism of cracks was analyzed and the guidance for optimizing process parameters was proposed.

     

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