激光立体成形TC4钛合金动态剪切特性研究

采用微型霍普金森压杆装置和双剪切试样对激光立体成形TC4钛合金的高应变率动态剪切特性进行了研究.通过数值模拟方法从应力、应变均匀性和应力三轴度方面对双剪切试样的缺口形状、剪切区宽度和长度进行优化设计.采用实验方法，分析了不同取向的激光立体成形沉积态TC4钛合金的高应变率（10⁴ s^-1量级）剪切性能.结果表明，动态剪切力学性能并没有明显的各向异性，流动应力随应变率的增大而增加，二者大致呈线性关系.

Study on Dynamic Shear Properties of Laser Solid Forming TC4 Titanium Alloy

Dynamic shear fracture is one of common failure modes of ductile metals. The dynamic shear property of TC4 alloy fabricated by laser solid forming (LSF) was investigated with micro split Hopkinson pressure bar and double-notch shear (DS) specimen in this paper. The notch shape as well as width and length of shear zone of DS specimen were optimized by numerical simulation, by taking into account homogeneity of stress and strain as well as stress triaxiality. The mechanical properties of as-deposited LSF TC4 alloy in different orientations were studied experimentally at the order of shear strain rates of 10⁴ s^-1. The results show that there is no obvious anisotropy in dynamic shear property, while the flow stress increases with increasing strain rate and there is approximate linear relationship between them.