激光沉积制造TC4/TC11直接过渡界面组织及性能研究

通过激光沉积制造(LDM)技术制备了TC4/TC11双合金直接过渡试样,并对其进行了去应力及固溶时效热处理。采用光学显微镜(OM)、扫描电子显微镜(SEM)、万能试验机和硬度计对试样的显微组织和拉伸断口进行了观察,并对其拉伸性能和显微硬度进行了测试及分析。结果表明,沉积态TC4/TC11双合金过渡处网篮组织差异大,去应力退火后的组织均匀,经固溶时效处理后组织粗大且差异明显;对去应力退火后的试样进行了室温拉伸,TC4/TC11双合金直接过渡处的抗拉强度与TC4抗拉强度相近,TC4/TC11双合金直接过渡处的塑性低,拉伸断口为韧性断口,室温拉伸的断口均断在TC4钛合金一侧,证明了TC4/TC11双合金直接过渡界面的性能良好;对该双合金直接过渡处的组织分析解释了其硬度变化的趋势。

Microstructure and properties of direct transition interface of TC4/TC11 fabricated by laser deposition

TC4/TC11 direct-transition alloy samples were prepared by laser deposition technique, and the stress relief and solution aging heat treatments were carried out. The microstructure, tensile fracture were observed using optical microscope (OM), scanning electron microscopy (SEM) and universal testing machine, then the tensile properties and hardness were tested and analyzed. The results show that the basket-weave microstructures of two sides of the deposited TC4/TC11 differ greatly, the microstructure is much more uniform after stress relieving and the microstructure is coarser after solution-aging. After the tensile tests under ambient temperature on the stress-relieved samples, the minimum tensile strength of TC4/TC11 is located at the direct transition zone, which is close to that of TC4. TC4/TC11 has a low plasticity at the direct transition zone. The fracture sections at room temperature are all on the side of TC4 titanium alloy, which proves that the direct transition interface of TC4/TC11 has good properties. The microstructure analysis of the direct transition zone explains its micro-hardness variation.