中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 20 No. 11 November 2010 |
TiC+Ti powders
（1. School of Materials Engineering, Shanghai University of Engineering Science, Shanghai 201620, China;
2. National Engineering Research Center of Light Alloy Net Forming,
School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China）
Abstract: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.
Key words: TC4 Ti alloy; TiC; laser cladding; segregation; hardness
