(1. 江蘇大學(xué) 材料科學(xué)與工程學(xué)院，鎮(zhèn)江 212013；
2. 江蘇大學(xué) 江蘇省高端結(jié)構(gòu)材料重點(diǎn)實(shí)驗(yàn)室，鎮(zhèn)江 212013)
摘 要: 以Al-SiO2為反應(yīng)體系，借助半固態(tài)機(jī)械攪拌法，結(jié)合電磁攪拌分散工藝，制備5% α-Al2O3p/ZL109(體積分?jǐn)?shù))復(fù)合材料，并對重熔后的復(fù)合材料進(jìn)行擠壓鑄造成型研究。結(jié)果表明：擠壓鑄造顯著消除了復(fù)合材料因半固態(tài)機(jī)械攪拌卷氣而引起的嚴(yán)重氣孔缺陷，并細(xì)化基體α(Al)相晶粒；當(dāng)壓射比壓達(dá)到80 MPa時，氣孔缺陷完全消失，粗大的α(Al)樹枝晶轉(zhuǎn)變?yōu)榧?xì)小的等軸晶，針狀共晶Si細(xì)化成短棒狀；分布在晶界的α-Al2O3顆粒也在一定程度上細(xì)化α(Al)晶粒。經(jīng)80 MPa擠壓鑄造的重熔復(fù)合材料的T6熱處理態(tài)抗拉強(qiáng)度和布氏硬度分別達(dá)到347 MPa和136 HB，與ZL109基體相比，提高5.8%和5.4%；與未擠壓復(fù)合材料相比，提高20.9%和18.3%。
關(guān)鍵字: Al-SiO2體系；α-Al2O3p/ZL109復(fù)合材料；擠壓鑄造；顯微組織；力學(xué)性能
（1. School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013, China;
2. Jiangsu Province Key Laboratory of High-end Structure Materials, Jiangsu University, Zhenjiang 212013, China）
Abstract:5% α-Al2O3/ZL109 (volume fraction) composites were prepared by semi-solid mechanical stirring with aid of electromagnetic stirring through Al-SiO2 system, and the remelted composites were also studied by squeeze casting. The microstructure observation results show that squeeze casting is very effectively to eliminate serious porosity defects caused by semi-solid mechanical stirring and refine the microstructure of ZL109 matrix. When the squeeze pressure reaches 80 MPa, the porosity defects completely disappear, coarse α(Al) dendrites transform into fine equiaxed crystals, and the eutectic Si is refined into rod-like. α-Al2O3 particles distributing along grain boundaries also refine α(Al) grains to some extent. The mechanical property test results show that the tensile strength and Brinell hardness of T6-treated composites remelted at 80 MPa are 347 MPa and 136 HB, respectively, which increase by 5.8% and 5.4% compared with those of remelted ZL109 matrix alloy, and increase by 20.9% and 18.3% compared with those of non-squeeze casting composites.
Key words: Al-SiO2 system; α-Al2O3/ZL109 composite; squeeze casting; microstructure; mechanical property
