激光沉积Ti65钛合金拉伸性能

Tensile Property of Laser Deposition Ti65 Titanium Alloy

激光增材制造钛合金构件室温及高温条件下的力学性能对航空发动机在复杂服役环境下的应用具有重要意义。采用激光沉积制造技术制备Ti65钛合金试样,对水平和竖直取样方向试样在室温和高温条件下的拉伸性能及断口形貌进行分析,为激光沉积Ti65钛合金在宽温度范围内的力学性能提供科学依据。结果表明:室温和高温条件下,水平方向试样的塑性差、强度好,竖直方向试样的塑性好、强度差。主要原因在于水平方向晶界数量较多,晶界有效阻碍滑移运动促使强度升高塑性降低。高温条件下,不同取样方向试样的抗拉强度及屈服强度随着试验温度升高均呈下降趋势,延伸率呈增大趋势。因为高温使原子动能增加,位错运动阻力降低。观察断口发现,室温下水平试样和竖直试样的断裂方式分别为脆性断裂和准解理断裂,高温下所有试样均为韧性断裂。

The mechanical properties of laser additive manufacturing of titanium alloy components under room temperature and high temperature conditions are important to the application of aero engines in complex service environments.Therefore,the Ti65 titanium alloy specimen was prepared by laser deposition manufacturing technology.The tensile properties and fracture morphology of the horizontal and vertical sampling direction samples under room temperature and high temperature conditions were analyzed,which provided a scientific basis for the mechanical properties of laser deposition Ti65 titanium alloy in a wide temperature range.The results show that under room temperature and high temperature conditions,the horizontal specimen has high strength and low plasticity,while the vertical direction sample has low strength and high plasticity,mainly because of the number of grain boundaries in the horizontal direction is large,and the grain boundaries effectively hinder the slip movement,leading to an increase in strength and a decrease in plasticity.Under high temperature conditions,the tensile strength and yield strength of specimens in different sampling directions showed a decreasing trend with the increase of test temperature,and the elongation showed an increasing trend.Because high temperatures increase atomic kinetic energy,the resistance to dislocation motion decreases.Fracture observation shows that the fracture methods of horizontal specimens and vertical specimens at room temperature are brittle fracture and quasi-cleavage fracture,respectively,and all samples are ductile fractures at high temperature.