Analysis of microstructure, texture and high-temperature durability of TC4 titanium alloy by different molds

Abstract:

Investigate the microstructure, texture and high-temperature endurance properties of TC4 titanium alloys under different molds. the optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM), and electron back scattering diffraction (EBSD) were used to observe and analyze the microstructure and persistent fracture behavior of TC4 titanium alloy.The results show that the phases of TC4 titanium alloy by different molds are all composed of α phase, β phase and ω phase, and the main phase is α phase (about 90%). Compared with the graphite type, the ceramic type is favorable for the β→α phase transition, the α phase is 5.3% higher, the average grain size is large (dmean = 37.021μm), the grain boundaries are less, and the grains are relatively uniform and relatively stable. When it is large, the material strength decreases and the plasticity increases. Simultaneously, the ceramic-type texture has high strength and obvious orientation. The texture type is {11-20} <1-100>, and the angle with the Y direction is about 45°, it further verified that the samples are in (101), (002),(101) .The reason for the increase in peak intensity is related to the formation of texture，The high temperature durability of ceramic samples is better than that of graphite. At the temperature (400℃，430℃，460℃), the persistent stress fracture life has increased by 1.174%, 15.401, 6.998%, all of which are ductile fracture. Appearance is a dimple pattern. In addition, temperature directly affects the long-term life of TC4 titanium alloy. as the temperature increases, the stress fracture life of TC4 titanium alloy gradually decreases.

Key words:TC4 titanium alloy,mold, microstructure,texture; high temperature durability