送粉激光熔覆成形L合金试验研究

利用L合金粉末,开展了激光熔覆技术修复基体2C r12的研究。对修复件的显微组织进行了分析,并对修复件的拉伸、冲击性能进行了测试。组织分析表明:熔覆层与基体形成良好冶金结合;每层中间部位基本上为垂直于结合面外延生长的柱状树枝晶,其生长方向基本一致;熔覆层上部组织主要由枝晶组成,其生长方向不同于底部组织,生长方向基本与激光扫描方向平行。拉伸、冲击试验证明,L合金粉末修复件沿激光扫描方向的延伸率约为18%~30%,垂直激光扫描方向由于受内部道和道间搭接影响,延伸率约为10%~18%。激光熔覆区断口主要由韧窝和撕裂棱组成,呈现明显的韧性断裂特征。试验表明:送粉激光熔覆能够获得表面平整,无裂纹、气孔等缺陷的制件;熔覆层具有较好的拉伸、冲击强度和较好的韧性;熔覆层沿激光扫描方向(纵向)性能略优于垂直激光扫描方向(横向)的性能。

Experiment on Injection Powder Laser Cladding Forming L-Alloy

The laser cladding forming L-alloy on the substrate 2Cr12 is studied.The microstructure and mechanical properties of the tensile and impact strength are tested.Results show that the metallurgic bonding structure can be acquired between the cladding material and the substrate.Usually normal to the bonding surface,the epitaxial growth dendrite is formed on the middle part of each cladding layer.The microstructure of the top part is mainly made up of the dendrite.Different to the bottom microstructure,its growth direction is more likely parallel to the laser scanning direction.The ductile rate of the cladding L-alloy along the laser scanning direction is about 18%-30%.Normal to the laser scanning direction,due to the influence of the overlap on cladding layers,the ductile rate is approximately 10%-18%.The fracture surface of the cladding area is made up of dimples and tearing ridges,and the fracture shows ductile rupture properties.Experimental result shows that,with the side injection powder laser cladding method,smoothed multi-layer overlapping components without cracks are fabricated.The cladding layers have good tensile,impact strength,and good ductility.The longitudinal properties of cladding layers are better than that of the cross direction.