( 1. 南京大學(xué) 物理系， 南京 210093;
2. 東南大學(xué) 材料科學(xué)與工程系， 南京 210096)
摘 要: 采用納米級(jí)顆粒增強(qiáng)的鎂基復(fù)合材料可望比微米級(jí)復(fù)合材料具有更好的力學(xué)性能。采用納米n-SiCp作為增強(qiáng)體，復(fù)合粉體經(jīng)機(jī)械合金化、 真空熱壓和熱擠壓得到了致密的n-SiCp/MB2鎂基復(fù)合材料。進(jìn)行了熱擠壓態(tài)組織觀察， 測(cè)試了擠壓態(tài)復(fù)合材料的氣孔率、 硬度、 常溫和高溫力學(xué)性能。 結(jié)果表明： 制備的n-SiCp/MB2復(fù)合材料致密且SiCp分布均勻， 增強(qiáng)體/基體界面結(jié)合良好， 基體中無(wú)明顯的位錯(cuò)， 基體晶粒尺寸小于300 nm； 復(fù)合材料的硬度、 常溫和高溫力學(xué)性能比基體合金的高，但塑性下降； 復(fù)合材料拉伸斷口存在韌窩， 高溫拉伸斷口上的韌窩更深。
關(guān)鍵字: 鎂； 碳化硅； 復(fù)合材料
WANG Lei1, SUN Yang-shan2
（ 1. Department of Physics, Nanjing University, Nanjing 210093, China;
2. Department of Materials Science and Engineering,
Southeast University, Nanjing 210096， China）
Abstract: n-SiCp/MB2 magnesium matrix composites are fabricated by mechanical alloying, vacuum hot-press and hot extrusion, because it is possible that the composites may have better properties for using smaller nanoparticles as reinforcement. The cavity, hardness, mechanical properties at room and elevated temperatures of the as-extruded composites were tested. Microstructural observation shows that the SiC nanoparticle is uniformly distributed, the n-SiCp/Mg interface is bonded very well, and there are no microcavity, reactive product and dislocations in the matrix alloy near the interface area. The grain size of n-SiCp/MB2 composites is smaller than 300 nm and also smaller than that of MB2 alloy. Hardness, tensile properties at room and elevated temperatures of the as-extruded composites are higher than those of MB2 alloy; but the plasticity decreases. Small size dimples and little amount of SiCp are obsreverd on the fracture surface, and the dimples become more deep with the tensile temperature increasing.
Key words: magnesium; silicon carbide; composite
