La含量对钼制品制备过程中组织和性能的影响

Effect of La content on microstructure and mechanical properties of Mo products in preparation process

利用金相显微镜(OM),扫描电子显微镜(SEM)及透射电镜(TEM)对钼制品制备过程中组织演变进行研究,并分析La含量对制备过程中组织和性能的影响。结果表明:随La含量升高,粉末的粒度变细,比表面积增加;添加微量La,可提高钼制品旋锻态的抗拉强度和伸长率,随La含量升高,钼制品旋锻态的抗拉强度升高,当添加1.0%La(质量分数)时达到最大值647.9 MPa,而伸长率先升高后降低,在0.1%La时达到最大值44.7%;透射电镜的分析显示,钼制品旋锻态中的第二相颗粒为分布在晶粒内部的La_2O_3颗粒,可阻碍和储存位错以提高材料的强度和韧性。钼制品拉拔态的抗拉强度则随退火温度的升高而降低,在各个温度退火后,添加0.03%La时的抗拉强度均为最高;并且纯钼制品拉拔态的再结晶温度为1 300℃,掺La钼制品拉拔态的再结晶温度高于1 700℃。

The microstructure of Mo products in the preparation process was investigated by optical microscopy （OM）, scanning electron microscopy （SEM） and transmission electron microscope （TEM）, and the effect of La content on the microstructure and mechanical properties was also analyzed. The results show that the size of the powder decreases with the increasing of the La content; the addition of La can increase the tensile strength and elongation rate of the rotary swaged Mo, with increasing La content, the tensile strength increases and reaches the maximum value of 647.9 MPa when adding 1.0%La, and while the elongation rate increases at first then decreases and reaches the maximum value of 44.7% when adding 0.1%La; The transmission electron microscope analysis shows that the second phase particles in the rotary swaged Mo are La2O3 particles which distribute in the grain interior and can hinder and store the dislocations to improve the strength and toughness. The tensile strength of the drawn Mo decreases with increasing annealing temperature and reaches the maximum value at 0.03%La in reached annealing temperatures; moreover, the recrystallization temperature of the drawn pure Mo is 1 300℃, while the recrystallization temperature of drawn Mo-La is above 1 700 ℃.