Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-31 Cooperative journals: 《材料研究学报》
Abstract： Pre-alloyed powders of T55 have been hot-isostatic-pressed (HIPed) at different HIPing temperatures, and the powder compacts were solution- and aging- treated. Thereafter the powder compacts were carefully examined to establish the relationship between their microstructure and mechanical property. Powder compacts HIPed at 940℃ and 970℃ showed no significant difference on the microstructure and tensile properties. Due to the densification wave effect caused by a non-uniformity of temperature/pressure field during HIPing, the recommended HIPing temperature is 940℃ in this work. The tensile property of powder compact at 600℃ was improved obviously after solution- and aging- treatment. The tensile property of the heat-treated powder compact is close to that of the wrought alloy but better than those of the cast ones. Finite element analysis was used to predict the final dimensions of the small casing component after HIPing, which is well consonant with the experimental data, thus, the FEM analysis is an efficient method for the design and manufacture of powder components. Based on the optimal container design and FEM analysis, a large thin-wall cylindrical structure of Ti55 alloys was manufactured successfully.
Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-19 Cooperative journals: 《金属学报》
Abstract： Microstructure and texture of titanium alloy are determined by thermomechanical and heat treatments and can significantly affect the mechanical properties of the final products. In this work, the microstructure and texture evolution during the heat treatment in a /b and b phase field in Ti60 precision forging bars were investigated. The results implied that the actual deformation temperature gradually decreased during precision forging processes. The microstructure and texture of Ti60 bar were determined by the finish forging temperature and the diameter, and strong microtexture macrozones existed in the forged Ti60 bar. For the bar with diameter of 45 mm (D45), the finish forging temperature fell in the lower temperature region of the a /b phase field, and the main a textures in these bars were <0001> and <101ˉ0> fiber texture components in initial Ti60 bar. The similarity of the microstructure and texture were found after heat treatment at 950 ℃. The intensity of <101ˉ0> fiber texture gradually decreased while that of <0001> fiber texture increased with the increase of the heat treatment temperature. Heat treatments have little influence on the strength of forged Ti60 bars of D45, while their ductility was reduced after b heat treatment. For the bar with diameter of 30 mm (D30), the finish forging temperature was below the a /b phase field, and the main a texture in those bars was <101ˉ0> fiber texture component. The intensity of <0001> fiber texture in those bars increased while that of <101ˉ0> fiber texture gradually decreased with the increase of the heat treatment temperature. Their room temperature strength significantly increased with the increase of the heat treatment temperature, and yield strength and tensile strength reached to 1086 and 1144 MPa, respectively, but the elongation only 3.3% after b heat treatment.
Subjects: Materials Science >> Materials Science (General) submitted time 2016-11-04 Cooperative journals: 《金属学报》
Abstract：α/β两相区精锻的Φ30mm和Φ45mm Ti60棒材分别在950℃、1000℃、1050℃固溶+时效热处理，研究了棒材显微组织、织构及其对拉伸性能的影响。结果表明，Φ45mm棒材中存在较强的和平行于棒材轴向的丝织构；950℃热处理后显微组织和织构变化不明显；随固溶温度升高，晶体方向平行于棒材轴向的丝织构增强，而丝织构密度减弱；固溶温度对棒材强度的影响不大。Φ30mm棒材中主要存在方向平行于棒材轴向的丝织构，固溶温度升高，晶体方向与棒材轴向平行的织构逐渐增强，棒材的室温强度随固溶温度升高而显著升高。
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