激光功率对Ni基合金熔覆层的结构及性能影响

Effects of laser power on microstructure and properties of Ni-based alloy cladding layers

本文通过研究激光功率对Ni基合金熔覆层的组织结构及抗磨耐蚀性能的影响,寻求最佳的激光功率参数,以求获取冶金结合良好,耐磨及耐蚀性优异的Ni基合金涂层。研究结果表明,熔覆制备的Ni基合金涂层与基体呈现冶金结合,无明显的裂纹及孔洞,其主要成分为γ-(Ni,Fe)固溶体,并在较低的激光功率下伴随有少量的Cr3C7相出现。随激光功率增大,熔覆层中的Ni和Cr元素含量下降,Fe元素含量升高,熔覆层的厚度从545μm增加到1100μm,组织明显宽化,并有从树枝晶向胞状晶转变的趋势。同时,随激光功率增大,试样的显微硬度从508HV降低到375HV,耐磨性能随之下降,耐蚀性反而提升,自腐蚀电流密度从4.347×10^-7A/cm^2降低到8.257×10^-8A/cm^2。

The effects of laser power on the microstructure and wear-resistant and corrosion-resistant properties of Ni-based alloy cladding coatings were studied in this paper, in order to get the optimal laser power parameters and obtain Ni-based alloy coatings with good metallurgical bonding and excellent wear resistance and corrosion resistance. The results showed that Ni-based alloy coating prepared by laser cladding is metallurgically bonded to the substrate without obvious cracks and holes, and the main composition of the Ni-based alloy coating is γ-(Ni,Fe) solid solution, and a small amount of Cr3C7 phase appeared in relatively lower power. With increasing laser powers, the element contents of Ni and Cr in the cladding layers decreased, the element content of Fe in the cladding layers increased, and the thickness of cladding layers increased from 545 μm to 1 100 μm, microstructure was coarsened obviously and the transition from dendrites to cellular dendrites tendency. Meanwhile, with increasing laser powers, the microhardness decreased from 508 HV to 375 HV, and the wear resistance of the specimens decreased, but the anti-corrosion resistance was enhanced, the corrosion current density decreased from 4.347×10^-7 A/cm^2 to 8.257×10^-8 A/cm^2.