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Inconel 718合金激光增材修复关键工艺优化

Optimization of key technology of Inconel 718 alloy by laser additive repair

  • 摘要: 为了进一步优化制备试样的成形质量并延长其服役寿命,首先探究了工艺参数对激光增材修复Inconel 718合金成形质量及力学性能的影响,采用正交设计试验方法进行Inconel 718合金单道沉积层熔覆试验,观察了不同工艺参数下单道熔覆层的表面形貌并测量其宽度和高度,通过极差值与排序结果,分析工艺参数对单道熔覆层几何形状的影响规律,得到3个主要的工艺参数对单道熔覆层形貌的影响排序,从而获得最优的工艺参数组合;之后,利用调控后的工艺参数成功制备出无裂纹、孔隙等缺陷的块状Inconel 718合金试样,选择激光功率为主要探究因素,研究激光功率对熔覆块状Inconel 718合金显微组织、硬度、抗拉强度和断后伸长率的影响,构建工艺参数,显微组织与力学性能间的联系. 结果表明,激光功率和粉末供给速率分别为影响熔覆高度和宽度的主要因素;当激光功率为1600 W,扫描速度为12.5 mm/s,送粉速率为8 g/min时,由于温度梯度和冷却速度的影响,熔覆试样的微观组织致密、晶粒细小,枝晶间距适当,具有优异的抗拉强度和断后伸长率.

     

    Abstract: In order to further optimize the forming quality of the samples and prolong its service life, this paper explores the influence of process parameters on the forming quality and mechanical properties of Inconel 718 alloy repaired by laser cladding , and carries out the single track cladding experiment of Inconel 718 alloy by orthogonal design, observes the surface morphology of the single track cladding layers with different process parameters and measures its width and height. Through the extreme difference and ranking results, the influence law of process parameters on the geometry of single track cladding layers are analyzed, and the influence order of three main process parameters on the morphology of single track cladding layers are obtained, so as to obtain the optimal combination of process parameters. Then, the bulk Inconel 718 alloy samples without cracks, pores and other defects are successfully prepared by using the adjusted process parameters. The influence of laser power on the microstructure, hardness, tensile strength and elongation after fracture of the cladding bulk Inconel 718 alloy are studied, and the relationship between process parameters, microstructure and mechanical properties is constructed. The results show that laser power and powder feeding rate are the main factors affecting the cladding height and width respectively. When the laser power is 1600 W, the scanning speed is 12.5 mm/s, and the powder feeding rate is 8 g/min, due to the influence of temperature gradient and cooling rate, the microstructure of the cladding sample is compact, the grain size is fine, the dendrite spacing is appropriate, and The sample has excellent tensile strength and elongation after fracture.

     

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