中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 24 No. 9 September 2014 |
（Engineering Research Center of Ministry of Education on Laser Direct Manufacturing for Large Metallic Components,
School of Materials Science and Engineering, Beihang University, Beijing 100191, China）
Abstract:TA2/TA15 graded structural material (GSM) was fabricated by the laser additive manufacturing (LAM) process. The chemical composition, microstructure and micro-hardness of the as-deposited GSM were investigated. The results show that the TA2 part of exhibiting near-equiaxed grains was Widmanst？tten α-laths microstructure. The TA15 part containing large columnar grains was fine basket-weave microstructure. The graded zone was divided into four deposited layers with 3000 μm in thickness. As the distance from the TA2 part increases, the alloy element contents and the β phase volume fraction increase, the α phase volume fraction decreases and the microstructure shows the evolution from Widmanst？tten α-laths to basket-weave α-laths gradually. The micro-hardness increases from the TA2 part to the TA15 part due to the solid solution strengthening and grain boundary strengthening.
Key words: laser additive manufacturing; TA2/ TA15; graded structural material; microstructure; chemical composition
