Phase Transformation of Stress Induction on Ti-6Al-4V Alloy

• Main Authors: Wun-Kai Wang, 王文楷
• Other Authors: Lay-Gaik Teoh
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/17816013605421780678

碩士 === 國立屏東科技大學 === 機械工程系所 === 98 === Ti-6Al-4V alloy was forging in different temperatures processed, different forging ratio, after 450~550℃ heat treatment, by X ray diffraction (XRD) and scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) observation. In accordance with the experimental result, alloy from 800℃ forging, Low forging ratio and high forging ratio, the microstructure is fine-grained α + α + α"+ β-phase. By XRD (0002) diffraction peak is the maximum. Alloy from 950℃ forging, Low forging ratio, the microstructure is equiaxed α + lath α + acicular martensite α' + α" + β-phase. High forging ratio, non-thermal reaction ω-phase precipitation. By XRD (0002) and (01-11) diffraction peak is the quite.Alloy from 1050℃ forging the microstructure is α' + α' + α" + β-phase. By XRD (01-11) diffraction peak is the maximum. Microstructure is Hexagonal-Closed-Packed (H.C.P) microstructure of α-phase, acicular martensitic structure of α'-phase, ω-phase and the orthorhombic α"-phase. Body-Centered-Cubic (B.C.C) structure of the β-phase, The lattice parameter of α-phase is a=0.295nm、c=0.466nm，c/a ratio of 1.579; α'-phase with a = 0.291nm, c = 0.465nm, c/a ratio of 1.597; α"-phase with a = 0.303nm, b = 0.492nm, c = 0.466nm; ω-phase with a = 0.468nm, c = 0.293nm; β-phase with a = 0.327nm. Key words: Titanium alloy, Forging, Texture.