激光熔覆铁基合金涂层的组织及摩擦磨损性能

Microstructure and Friction and Wear Properties of Fe-based Alloy Coatings by Laser Cladding

利用激光熔覆技术在20CrNi2MoA钢表面制备铁基合金涂层。研究了激光功率对熔覆层显微组织、显微硬度的影响,分析了熔覆层和基体的摩擦磨损性能。结果表明:熔覆层组织由内及表依次为平面晶-胞状晶-树枝晶-等轴晶,无裂纹、气孔等缺陷,与基体呈良好的冶金结合。在一定功率范围内,激光功率增加使得枝晶尺寸增大以及显微硬度下降。在相同磨损参数下,激光功率为2.5、2.8 kW时熔覆层磨损量为7.35×10^(-3)mm^3和1.401×10^(-2)mm^3,相对耐磨性为基体的10.3倍和5.42倍,稳定磨损阶段熔覆层摩擦系数在0.24和0.26左右,而基体稳定在0.35左右。

Fe-based alloy coating on 20CrNi2MoA steel surface was prepared by laser cladding. The effects of laser power on the microstructure and microhardness of the cladding layer were studied. The friction and wear properties between cladding coating and matrix were analyzed. The results show that the microstructure from inner to surface is fiat crystal-cellular crystal-dendrites-equiaxed crystal, there is no cracks, holes and other defects. The cladding layer has a good metallurgical bonding with matrix. Within a certain power range, the increase of laser power leads to the increase of dendrite size and decrease of microhardness.Under same wear parameters, the wear loss value of the cladding layer under the power of 2.5 kW and 2.8 kW is 7.35 ×10^-3mm^3 and 1.401×10^-3mm^3, respectively. The relative wear resistance of cladding layer is 10.3 times and 5.42 times of matrix. The friction coefficient of the cladding layer under the power of 2.5 kW and 2.8 kW in stable wear stage is about 0.24 and 0.26, respectively, while the substrate is around 0.35.