Research of laser rapid forming Ti40 burn resistant titanium alloy

Laser rapid forming(LRF), a deposition forming process which can be utilized to produce three-dimensional engineering structures line by line and layer by layer, is a promising technology for the rapid prototyping and manufacturing of complicated metal components. In the present paper, the LRF process for both thin-walled and block components of a Ti40 bum-resistant titanium alloy(Ti-25V-15Cr-0.2Si) were investigated. The microstructures of the deposited Ti40 alloy were studied by Optical Microscopy (OM), Scanning Electronic Microscopy (SEM) observation and X-Ray Diffraction (XRD) analysis. The mechanical properties were evaluated by tensile test. The results show that defect-free and homogeneous deposited layers can be formed under optimum processing condition. Both the thin-walled and the block as-LRFed samples present the β phase microstructure, with equiaxed grains in the former but columnar ones in the latter case, respectively. The maximum room-temperature tensile strength of as-LRFed samples achieves 997MPa, while the tensile elongation is as high as 20%. The fractograph of tensile sample show mixed characteristics, which consists of intracrystalline dimple fracture and transgranular cleavage fracture.