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采用激光熔覆技术在QAl9-4铝青铜表面熔覆了一层Ni基合金层,以提高QAl9-4铝青铜的耐磨性。为了提高QAl9-4铝青铜对激光的吸收率,实验采用少量自制的粘结剂并配合压力机将合金粉末预置在QAl9-4铝青铜表面,然后激光重熔。通过对QAl9-4铝青铜表面熔覆层组织研究分析表明:熔覆层与基体形成了良好的冶金结合,无裂纹缺陷的存在;熔覆层组织受凝固速度的影响较大,其表面组织为胞状晶,中部为发达的树枝晶,结合区上部由于基体的激冷作用而呈细晶区,细晶区以下又以树枝晶和胞状晶为主。激光熔覆层的平均硬度是QAl9-4铝青铜基体硬度的3倍多。
A layer of Ni-based alloy was cladded on the surface of QAl9-4 aluminum bronze by laser cladding to improve the wear resistance of QAl9-4 aluminum bronze. In order to improve the laser absorption rate of QAl9-4 aluminum bronze, a small amount of self-made adhesive was used in experiment and the alloy powder was preset on the surface of QAl9-4 aluminum bronze with a press, then laser remelted. Through the analysis of the microstructure of the QAl9-4 aluminum bronze surface cladding layer, the metallurgical bonding between the cladding layer and the substrate shows that the microstructure of the QAl9-4 aluminum bronze surface is not cracked. The microstructure of the cladding layer is greatly influenced by the solidification rate. Cellular crystals, the central part of the developed dendrites, the junction of the upper part of the base due to the chilling effect was fine crystal region, the fine crystal region followed by dendrites and cellular crystal-based. The average hardness of the laser cladding is more than 3 times the hardness of QAl9-4 aluminum bronze matrix.