河野紀(jì)雄2，齊藤秀雄3
(1.哈爾濱工業(yè)大學(xué) 材料科學(xué)與工程學(xué)院， 哈爾濱 150001;
2.日本千葉工業(yè)大學(xué) 金屬工學(xué)科;
3.日本千葉工業(yè)大學(xué) 附屬材料解析中心)
摘 要: 選用5.0和0.15μm兩種粒徑的Al2O3顆粒，制備了Al2O3體積分數(shù)為40%的鋁基復(fù)合材料。利用透射電鏡對兩種復(fù)合材料拉伸前后的組織進行觀察，結(jié)果表明：5μm尖角形Al2O3顆粒增強復(fù)合材料的鑄態(tài)組織中存在高密度的位錯，這主要是由于熱錯配應(yīng)力引起的；0.15μm橢球形Al2O0顆粒增強復(fù)合材料的鑄態(tài)組織中幾乎觀察不到位錯，這與顆粒細小且為等軸狀、分布彌散、界面附近應(yīng)力分布均勻等因素有關(guān)。對拉伸斷口附近顯微組織的觀察表明，前者基體中位錯進一步增殖，后者則存在明顯的位錯環(huán)。室溫拉伸結(jié)果表明亞微米Al2O3p/Al復(fù)合材料中的這種微觀組織有利于材料強度和塑性的提高。
關(guān)鍵字: 金屬基復(fù)合材料；顯微組織；力學(xué)性能
microstructure and properties of
Al2O3p/Al composites
CHEN Jian-feng1, Norio Kouno2, Hideo Saito3
（1.Department of Materials Science and Technology, Harbin Institute of
Technology, Harbin 150001, China;
2.Department of Metallurgical Engineering, Chiba Institute of
Technology, Japan;
3.Analysis Center of Materials, Chiba Institute of
Technology, Japan）
Abstract:Aluminum matrix composites with alumina particles of 40%(volume fraction) were fabricated using 5.0μm and 0.15μm Al2O3 particles respectively. The microstructure of the two kinds of composites before and after tension was investigated with transmission electron microscope (TEM). It was found that there was a high dislocation density in the as-cast composite reinforced by 5?μm sharp-angle-shaped Al2O3 particle s, due to the thermal mismatch stress. In contrast, little dislocation was observed in the as-cast composite reinforced by 0.15?μm spherical Al2O3 particles, which could be attributed to the following factors, such as the dispersion of the equiaxed fine particles, uniform distribution of the stress near the interfaces, etc. The microstructural observation near the fracture indicated that dislocations increased in the matrix of the former composite, while obvious dislocation loops were found in the latter. The room temperature tensile test confirmed that such microstructure in the sub-micro Al2O3p/Al composites was beneficial to an increase in their strength and ductility.
Key words: metal matrix composites; microstructure; mechanical properties
