退火工艺对钼钨合金微观组织和性能的影响研究

Effect of Annealing Process on Microstructure and Properties of Molybdenum-Tungsten Alloy

本文采用粉末冶金烧结+旋锻方法制备了∅6.0 mm钼钨(Mo-50W)合金棒材,研究了退火温度对钼钨合金棒材微观组织和力学性能的影响,结果表明:退火温度对粉末冶金+旋锻成形钼钨合金棒材的力学性能有明显影响,当退火温度从1250℃升高到1450℃时,合金的抗拉强度从301 MPa降低到258 Mpa,延伸率由15.6%升高到18.5%;当温度超过1450℃时,合金棒强度进一步降低至251 Mpa,而延伸率也下降至17.9%。在1450℃出现明显性能拐点的原因是合金在1450℃退火后基本实现了完全再结晶,当退火温度低于该温度时,随温度提高,加工硬化迅速消失,强度与硬度迅速下降,塑性提高;当退火温度高于该温度时,发生再结晶晶粒长大,强度和硬度缓慢下降,同时塑性也下降。

In this paper,the molybdenum-tungsten(Mo-50W)alloy bars of 6.0 mm were prepared by powder metallurgy and rotary forging.The effect of annealing temperature on microstructure and mechanical properties of molybdenum-tungsten alloy bars was discussed.The results show that,the annealing temperature has a significant effect on the mechanical properties of Mo-W alloy bars formed by powder metallurgy and rotary forging.When the annealing temperature was raised from 1250℃to 1450℃,the tensile strength of the alloy decreased from 301 MPa to 258 MPa,and the elongation increased from 15.6%to 18.5%.When the annealing temperature was over 1450℃,the strength of the alloy rod further decreased to 251 MPa and the elongation decreased to 17.9%.The obvious inflection point at 1450℃is due to the complete recrystallization of the alloy after annealing at 1450℃.when the annealing temperature is lower than this temperature,the work hardening disappears rapidly,the strength and hardness decrease rapidly,and the plasticity increases.When the annealing temperature is higher than this temperature,the recrystallization grains grow,the strength and hardness decrease slowly,and the plasticity also decreases.