退火处理对电真空器件用钼棒组织及力学性能的影响

摘要

The diameter of 3 mm molybdenum bar of vacuum electronic device was prepared by powder metallurgy and swaging method, and the effect of annealing temperature on the microstructure and the mechanical properties of the molybdenum bar was discussed.The results show that, when the deformation of molybdenum bar reaches 90%,the recrystallization temperature of molybdenum bar appears at 1 000 ~1 050 ℃; before 1 000 ℃, with the increase of annealing temperature, the microstructure of molybdenum bar fiber becomes wider and the fiber lap decreases.At this stage, the tensile strength of molybdenum rods decreases and the elongation increases gradually,and the microstructure of molybdenum rod fibers decreases gradually at 1 000 ~1 200 ℃.The mechanical properties of molybdenum bar is optimized when the annealing process is 950 ℃ for 1 h, the tensile strength reaches the maximum value of 777 MPa, the elongation reaches the maximum value of 49.5%, the mechanical performance is better than the ASTM standard of USA.%本文采用粉末冶金+旋锻法制备了电真空器件用φ3.0 mm钼棒,分析了不同退火温度对钼棒的纤维组织及力学性能的影响.结果表明:当钼棒变形量达到90%时,钼棒的再结晶温度出现在1000~1050 ℃;在1000 ℃以前,随着退火温度的升高,钼棒纤维组织逐渐宽化,纤维搭接逐渐减少.在此阶段,钼棒抗拉强度降低,延伸率逐步升高;在1000~1200 ℃时,钼棒纤维组织逐渐减少,当退火工艺为950 ℃保温1 h时,钼棒的室温力学性能达到最优,其抗拉强度达到最大值777 MPa,伸长率达到最大值49.5%,力学性能优于美国ASTM标准.