不同送粉速度对TC4钛合金表面激光熔覆的影响

采用光纤激光对TC4钛合金表面进行熔覆改性,研究送粉速度对熔覆工艺过程和熔覆层性能的影响。采用高速摄像机拍摄了加热粉末在空间的分布形貌,采用光学显微镜观察了熔覆层横截面形貌,采用EDS分析了熔覆层的氮含量分布,并测量了熔覆层横截面的显微硬度。实验表明,送粉速度较小时,粉末吸收少量激光能量,熔池较大,熔覆层宽而浅;送粉速度较大时,粉末吸收大量激光能量,熔池较小,熔覆层窄而深。当送粉速度较大时,熔覆层的氮元素含量和显微硬度均分布基本均匀,无明显梯度;随送粉速度增加,熔覆层显微硬度会增加,并稳定在约9.3 GPa。

Effect of Powder Feeding Rate on Laser Cladding of TC4 Titanium Alloy

The surface of TC4 titanium alloy was cladding modified by fiber laser,and the effect of powder feeding rate on cladding process and cladding layer performance was studied. The distribution morphology of the heating powder in space was photographed using high speed camera system,the cross section morphology of the cladding layer was observed using optical microscope,the nitrogen content of the cladding layer was detected using EDS and the cross section microhardness of the cladding layer was measured. The experimental results show that the powder absorbs a little laser energy when the powder feeding rate is low,the molten pool is large,and the cladding layer is wide and shallow. The powder absorbs a lot of laser energy when the powder feeding rate is high,the molten pool is small,and the cladding layer is narrow and deep. When the powder feeding rate is high,the nitrogen content and microhardness of the cladding layer are uniformly distributed without obvious gradient. With the increase of powder feeding rate,the microhardness of the cladding layer increases,and stabilizes at about 9. 3 GPa.