Study on Microstructural and Mechanical Properties of Plasma Transferred Arc Cladding of Chromium Powder on Titanium Alloy

• Main Authors: CHEN, WEI-REN, 陳維仁
• Other Authors: HUANG, HER-YUEH
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/c9tb5s

碩士 === 國立虎尾科技大學 === 材料科學與工程系材料科學與綠色能源工程碩士班 === 106 === In this study, chromium powder was cladded on the surface of Ti-6Al-4V alloy by the plasma transfer arc process, and heat input was controlled by welding parameters. In stationary conditions the other parameters, changing powder filler and presence or absence of different doped current parameters. The performance of cladded material was evaluated by microstructure and mechanical properties tests. The results showed that the microstructure of Ti-6Al-4V in general consists of equiaxed α enclosed by β phase. During cooling, β phase transformed to Widmanstätten alternate layer of α and β phases. The hardness of chromium powder plasma transfer arc cladded was increased approximately 100 HV than base metal. Energy dispersive x-ray analysis indicated that a very few diffusion was present between the base metal and chromium cladded layer. The cladded specimens x-ray diffraction patterns showed presence of compound like CrTi4 phase. The tensile strength and ductility of cladded specimens were far lower than that of the substrate. The fracture surfaces were examined under scanning electron microscope and the observed fracture surface was typical cleavage brittle fracture in the clad and substrate. Arc current of 80A had been identified of the most suitable current since it gave a very smooth fracture surface and brought the highest value of tensile strength and elongation.