Effect of isothermal annealing and plasma arc coating on mechanical properties for titanium stainless steel using laser welding

The isothermal annealing (IA) and plasma arc Ni-Cr-Co-Mox coating (PAC) processes were assisted by the laser welding procedure to improve the narrow bead and hardness. The fusing zone preserved the heterogeneous Ti bulk ultrafine structure, Ti laminar geometry, Ti-basketweave grains (BWG), and ζ-TiAl phase. In contrast, coated samples of the TiNi phase, plastic Ti heterogeneous structure, β’-TiAl layers, and TiCrFe boundary were obtained. A heterogeneous Ti structure and TiAl phase of the outer surface region were achieved by the 900o C – PAC samples on (σy) yield strength of 964 MPa, yield strain of 5.06% and 1200o C – PAC samples on (σy) yield strength of 1020 MPa, yield strain of 4.78%. At 314 and 301 HV, respectively, the hardness values of the fusion zone and heat-affected zone rose. For the PA-coated samples’ 1200o C-IA, the average hardness value in the fusion zone was 324 HV, however the average hardness values in the outer and inner surface layers dropped considerably to 219 HV. Maximum Peak Height of investigation revealed the various ranges: 15.909 µm for 450o C-PAC samples coating samples, 22.381 µm for 900o C-PAC coating samples, and 39.329 µm for 1200oC – PAC coating.