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以“溶胶喷雾干燥-纳米原位复合”法合成的超细/纳米W-0.3%Y复合粉末为原料,通过普通模压-预烧和在1800~1950℃下烧结制备了细晶钨。检测了细晶钨的显微硬度和抗拉强度,并利用扫描电镜(SEM)和X射线能量色散谱(EDX)观察了显微组织及断口形貌,研究了其烧结行为及断裂行为的变化。结果表明,微量稀土Y以Y2O3第二相粒子的形式均匀弥散分布于W晶粒的晶内和晶界处,能有效抑制W晶粒的长大,显著细化晶粒,提高其力学性能。微量稀土Y的添加改变了细晶钨的断裂形式,由纯W的沿晶断裂转变为细晶钨的沿晶断裂为主+部分穿晶断裂。
The ultrafine / nano W-0.3% Y composite powders synthesized by the “sol-gel spray-dry nanocomposite in situ” method were used as raw materials to prepare fine-grained tungsten by common molding-pre-sintering and sintering at 1800-1950 ℃. The microhardness and tensile strength of fine grained tungsten were measured. The microstructure and fracture morphology were observed by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The changes of sintering behavior and fracture behavior . The results show that the trace rare earth Y diffused uniformly in the grain boundary and the grain boundary of the second grain of Y2O3 in the form of Y2O3 second phase particles, which can effectively suppress the growth of W grains, remarkably refine the grains and improve their mechanical properties. The addition of trace rare earth Y changed the fracture mode of fine-grained tungsten, which was mainly the intergranular fracture of the fine-grained tungsten transformed from the intergranular fracture of pure W and the transgranular fracture of the part.