摘要
采用激光沉积制造(LDM)技术制备了γ-TiAl合金(Ti-48Al-2Cr-2Nb)试样,并对不同工艺条件(激光功率和扫描速度)下试样的相组成、显微组织及显微硬度进行了分析。结果表明,经LDM工艺制备的γ-TiAl合金显微组织特征为等轴状的初生晶粒内包含有细小层片状的γ、α2相和B2相;扫描速度恒定,随着激光功率的增加,初生等轴晶晶粒尺寸逐渐增大,晶内的α2相和B2相含量逐渐增加,γ相含量降低,合金显微硬度逐渐增大;激光功率恒定,随着扫描速度的增加,初生等轴晶晶粒尺寸逐渐减小,晶内的α2相和B2相含量逐渐减少,γ相含量增加,合金显微硬度逐渐增大。经综合分析认为激光功率1 200 W、扫描速度7mm/s为最佳的γ-TiAl合金LDM工艺参数。
The γ-TiAl samples （Ti-48Al-2Cr-2Nb） which was fabricated by laser deposition manufacturing （LDM） technique under different processing conditions （laser power and scanning speed） was studied by means of XRD, OM and hardness tester. It turns out that the as-deposited γ-TiAl appeared unique microstructure, i. e. , fine lamella of γ,α2 and B2 was embodied in the equiaxed primary grains; when the scanning speed keeps constant, with the laser power increasing, the diameter of primary equiaxed grain increases gradually, the percentage of fine lamellaα2 and B2 phase increases gradually, on the contrary, theγphase content decreases, and the micro-hardness of the samples increases gradually; when the laser power keeps constant, with the increase of scanning speed,the diameter of primary equiaxed grain reduces gradually, the percentage of fine lamella α2 and B2 phase reduces gradually, while, the 7 phase content increases, and the micro-hardness of the samples increases gradually. According to comprehensive analysis, the optimized processing parameter with laser power at 1 200 W and scanning speed at 7 mm/s is proposed.
出处
《应用激光》
CSCD
北大核心
2017年第1期7-10,共4页
Applied Laser
基金
国家自然科学基金资助项目(项目编号:51505301
51305280
51375316)
国家重点研发计划资助项目(项目编号:2016YFB1100504)
