中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 31 No. 10 October 2021 |
（1. School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024, China;
2. Key Laboratory for Materials Modification by Laser, Ion, and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024, China;
3. School of Materials Science and Engineering, Dalian Jiaotong University, Dalian 116028, China）
Abstract:Ti-Al-V-Nb alloys with the cluster formula, 12[Al-Ti12](AlTi2)+5[Al-Ti14](V,Nb)2Ti, were designed by replacing V with Nb based on the Ti-6Al-4V alloy. Single-track cladding layers and bulk samples of the alloys with Nb contents ranging from 0 to 6.96 wt.% were prepared by laser additive manufacturing to examine their formability, microstructure, and mechanical properties. For single-track cladding layers, the addition of Nb increased the surface roughness slightly and decreased the molten pool height to improve its spreadability. The alloy, Ti-5.96Al-1.94V- 3.54Nb (wt.%), exhibited better geometrical accuracy than the other alloys because its molten pool height was consistent with the spread layer thickness of the powder. The microstructures of the bulk samples contained similar columnar β-phase grains, regardless of Nb content. These grains grew epitaxially from the Ti substrate along the deposition direction, with basket-weave α-phase laths within the columnar grains. The α-phase size increased with increasing Nb contents, but its uniformity decreased. Along the deposition direction, the Vickers hardness increased from the substrate to the surface. The Ti-5.96Al-1.94V-3.54Nb alloy exhibited the highest Vickers hardness regardless of deposition position because of the optimal matching relationship between the α-phase size and its content among the designed alloys.
Key words: Ti-Al-V-Nb alloy; composition design; laser additive manufacturing; microstructure; mechanical properties
