摘要
Laser surface cladding was applied on a TC4 Ti alloy to improve its surface properties. Mixed TiC and Ti powders with a TiC-to-Ti mass ratio of 1：3 were put onto the TC4 Ti alloy and subsequently treated by laser beam. The microstructure and composition modifications in the surfaee layer were carefully investigated by using SEM, EDX and XRD. Due to melting, liquid state mixing followed by rapid solidification and cooling, a layer with graded microstructures and compositions formed. The TiC powders were completely dissolved into the melted layer during melting and segregated as fine dendrites when solidified. The inter-dendritic areas were filled with fine a＇ phase lamellae enrich in A1. Mainly due to the reduced TiC volume fraction with increasing depth, the hardness decreases with increasing depth in the laser clad layer with a maximum value of HV1400, about 4.5 times of the initial one.
Laser surface cladding was applied on a TC4 Ti alloy to improve its surface properties.Mixed TiC and Ti powders with a TiC-to-Ti mass ratio of 1:3 were put onto the TC4 Ti alloy and subsequently treated by laser beam.The microstructure and composition modifications in the surface layer were carefully investigated by using SEM,EDX and XRD.Due to melting,liquid state mixing followed by rapid solidification and cooling,a layer with graded microstructures and compositions formed.The TiC powders were completely dissolved into the melted layer during melting and segregated as fine dendrites when solidified.The inter-dendritic areas were filled with fine α' phase lamellae enrich in Al.Mainly due to the reduced TiC volume fraction with increasing depth,the hardness decreases with increasing depth in the laser clad layer with a maximum value of HV1400,about 4.5 times of the initial one.
基金
Project(J51402) supported by the Leading Academic Discipline Project of Shanghai Education Commission,China
Project(gjd08004) supported by the Foundation for Excellent Youth Scholar of China
Project(08QA14035) supported by the Shanghai Science and Technology Development Foundation, China
Project(0852nm01400) supported by the Special Foundation of Shanghai Education Commission for Nano-Materials Research, China
Project(08520513400) supported by Crucial Project of the Shanghai Science and Technology Commission,China
