摘要
在２０００℃，２０ＭＰａ压力下于１．３×１０－３Ｐａ真空中热压烧结１ｈ制备了含２０％ＺｒＣ颗粒（体积分数）的钨基复合材料。组织观察表明：ＺｒＣ颗粒比较均匀分布于Ｗ基体中，ＺｒＣ颗粒阻碍了Ｗ晶粒的长大，也妨碍了材料的致密化；由于ＺｒＣｐ／Ｗ界面处存在Ｗ及Ｚｒ元素的互扩散，得到了强的界面结合；部分Ｗ原子扩散到ＺｒＣ点阵中，形成了（Ｚｒ，Ｗ）Ｃ固溶体；随着温度提高，复合材料的抗弯强度逐渐提高，在８００℃达到最大值１０７４ＭＰａ，比室温强度７６２ＭＰａ提高４１％，而后又随温度继续上升而下降。ＺｒＣｐ／Ｗ复合材料这种好的高温强度主要是由于Ｗ基体随温度上升发生了由脆性到塑性的转变，使ＺｒＣ颗粒增强效果在高温得以充分发挥；位错强化、载荷传递和裂纹钉扎是ＺｒＣｐ／Ｗ复合材料的高温强化机理。
Tungsten matrix composites containing 20% ZrC particles (volume fraction) was prepared by hot pressing at 2 000 ℃, 20 MPa in a vacuum of 1.3×10 -3 Pa for 1 h. The results show that the ZrC particles are well distributed within the W matrix, and the growth of W grains is prevented by the ZrC particles during sintering; there is an interdiffusion of Zr and W in ZrC p/W interface, which results in a strong bond; a (Zr, W)C solid solution zone is formed in ZrC. As the temperature increased, the bending strength of ZrC p/W composites increases gradually and reaches its maximum value 1 074 MPa at 800 ℃, which is 41% higher than 762 MPa at room temperature. The excellent high temperature strength of composites is attributed to tungsten matrix transitting from brittle to ductile with increasing temperature, which makes the strengthening effect of ZrC particle be more significant at high temperature. The strengthening mechanism at high temperature is dislocation strengthening, load transfering and crack pinning.
出处
《中国有色金属学报》
EI
CAS
CSCD
北大核心
1999年第1期49-54,共6页
The Chinese Journal of Nonferrous Metals
基金
航天工业总公司"九五"重大预研项目
关键词
钨基
复合材料
高温强度
碳化锆
组织结构
tungsten matrix composites ZrC particle high temperature strength ductile brittle transition
