高压凝固原位自生Al_(2)O_(3)/Al复合材料微观组织与热膨胀性能研究  

Microstructure on Thermal Expansion Coefficient of In-Situ Al_(2)O_(3)/Al Composites by High Pressure Solidification

作　　者：陈志鹏 朱冬冬 王刚[1] 董多 王晓红 Chen Zhipeng;Zhu Dongdong;Wang Gang;Dong Duo;Wang Xiaohong(Anhui Key Laboratory of High Performance Nonferrous Metals,School of Materials Science and Engineering,Anhui Polytechnic University,Wuhu 241000,China;School of Mechanical Engineering,Quzhou University,Quzhou 324000,China)

机构地区：[1]安徽工程大学材料科学与工程学院安徽省高性能有色金属重点实验室,安徽芜湖241000 [2]衢州学院机械工程学院,浙江衢州324000

出　　处：《稀有金属》2024年第4期477-486,共10页Chinese Journal of Rare Metals

基　　金：国家自然科学基金项目(51801112,51704001,52071188);安徽省自然科学基金项目(2008085J23);浙江省自然科学基金项目(LQ20E010003);安徽省人才工程基金项目(Z17550020001)资助。

摘　　要：Al_(2)O_(3)颗粒增强铝基复合材料具有众多优异性能,使其成为汽车轻量化和电子封装等行业的首选材料。但随着Al_(2)O_(3)体积分数的增加,复合材料强度和硬度提升而塑韧性明显降低。主要是因为Al_(2)O_(3)强化相润湿性差而发生团聚现象。在Al-12Si粉末中添加不同含量的Fe_(2)O_(3)(1%与3%)粉末制坯。采用高压凝固(0.02,2.5和3 GPa)将坯料烧结。复合材料中Fe_(2)O_(3)与Al发生置换反应制得纳米级Al_(2)O_(3)颗粒。结果表明:复合材料由α-Al,β-Si,Fe_(2)O_(3)和新生成的Al_(2)O_(3)衍射峰组成,呈现“网状晶界+块状硅+基体”形貌。通过对“网状晶界”分析,发现网状晶界是由纳米级的Al_(2)O_(3)颗粒、部分未参与反应的Fe_(2)O_(3)以及反应生成的Fe相组成。在XRD图谱中无Fe相衍射峰是由于生成的Fe相含量较少并且其在Al中有一定的固溶度。另外,凝固的压力越高网状晶界越密集,Fe_(2)O_(3)含量越高网状晶界越明显。对比复合材料热膨胀系数第一次与第二次加热结果发现。第一次加热时,由于高压固溶的硅析出热膨胀系数(CTE)曲线有峰值出现。另外,由于Fe_(2)O_(3)自身的CTE值也较铝合金的小,加入Fe_(2)O_(3)含量高的材料的热膨胀系数反而较小。在第二次加热时,由于第一次加热后缓慢冷却,所以均无热膨胀系数峰值出现。并且第二次加热最大热膨胀系数值较第一次降低75%。Al_(2)O_(3) particle reinforced aluminum matrix composites exhibit excellent properties,such as high strength,high hardness,wear resistance and low coefficient of thermal expansion,making them the preferred material in aerospace,automotive light weight and electronic packaging industries.In the production,with the increase of Al_(2)O_(3) volume in the matrix,the strength and hardness of the composites were increased,while the plastic toughness was decreased.The main reason was that the wettability of Al_(2)O_(3) strengthening phase is poor,which leads to agglomeration when entering the matrix.In this paper,the nanometer Al_(2)O_(3) particle reinforced Al matrix composites were prepared by in-situ high-pressure solidification(0.02,2.5 and 3 GPa)to refine Al_(2)O_(3) particles and make them distribute.In these composites,Al_(2)O_(3) particles were produced in-situ by the substitution reactions of Fe_(2)O_(3) and Al.Compared with Al matrix composites which were directly added Al_(2)O_(3) particles,the composites of in-situ Al_(2)O_(3) particle possessed the characteristics of excellent interface bonding,good compatibility and nano-sized particles.Then the microstructure of the composites was analyzed by scanning electron microscope(SEM),X-ray diffraction(XRD)and energy dispersive spectrometer(EDS),and the effects of microstructure on density and thermal expansion of the composites were discussed.The results showed that Fe_(2)O_(3)/Al-12Si composites were composed ofα-Al,β-Si,Fe_(2)O_(3) and new product Al_(2)O_(3).The microstructure showed that the composites were mainly composed of"nano network grain boundary+bulk silicon+matrix".Through EDS analysis of the"network grain boundary",it was found that the network grain boundary was composed of nano-sized Al_(2)O_(3) particles,some Fe_(2)O_(3) particles were not involved in the reaction and Fe phase produced by the reaction.The non-Fe diffraction peak in XRD was due to the low content of Fe phase produced and a certain solid solubility in Al.Additionally,with the inc

关 键 词：高压凝固 原位自生Al_(2)O_(3)颗粒 微观组织 热膨胀系数(CTE) 

分 类 号：TB332[一般工业技术—材料科学与工程]