ZrCp/W复合材料的组织结构和高温强度
来源期刊：中国有色金属学报1999年第1期
论文作者：宋桂明 周玉 雷廷权 王玉金 郭英奎
文章页码：49 - 54
关键词：钨基复合材料，ZrC颗粒，高温强度，塑脆转变
Key words：tungsten matrix composites, ZrC particle, high temperature strength, ductile-brittle transition
摘 要：在2000℃， 20MPa压力下于1.3×10-3 Pa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。
Abstract: Tungsten matrix composites containing 20% ZrC particles (volume fraction) was prepared by hot pressing at 2000℃, 20MPa in a vacuum of 1.3×10-3Pa for 1h. The results show that the ZrC particles are welldistributed 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 ZrCp/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 ZrCp/W composites increases gradually and reaches its maximum value 1074MPa at 800℃, which is 41% higher than 762MPa 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.
