(1. 蘭州理工大學(xué) 有色金屬新材料國(guó)家重點(diǎn)實(shí)驗(yàn)室，蘭州 730050；
2. 青海大學(xué) 金屬材料研究所，西寧 810016)
摘 要: 采用粉末熱擠壓法制備硼酸鎂晶須增強(qiáng)鋁基復(fù)合材料，研究不同擠壓比對(duì)擠壓態(tài)復(fù)合材料微觀組織和性能的影響。結(jié)果表明：隨著擠壓比的增加，硼酸鎂晶須的排布取向逐漸趨向于材料的熱擠壓方向，晶須長(zhǎng)徑比有所減小，擠壓比為25:1時(shí)，材料力學(xué)性能達(dá)到最佳值，屈服強(qiáng)度、極限拉伸強(qiáng)度及伸長(zhǎng)率分別為113.5 MPa、230 MPa和7.0%；拉伸強(qiáng)度(UTS)相比擠壓態(tài)的6061鋁合金和擠壓比為9:1的復(fù)合材料分別提高了37%和25%；拉伸斷口分析表明，材料的失效形式以6061Al基體的韌性斷裂、晶須與基體間的脫粘以及晶須團(tuán)聚體的脆性開(kāi)裂3種形式為主。
關(guān)鍵字: 鋁基復(fù)合材料；硼酸鎂晶須；熱擠壓；斷口
（1.State Key Laboratory of Gansu Advanced Non-ferrous Metal Materials,
Lanzhou University of Technology, Lanzhou 730050, China;
2.Institute of Metal Materials, Qinghai University, Xining 810016, China）
Abstract:The Mg2B2O5 whisker reinforced Al matrix composites were fabricated using powder metallurgy routes. The effects of different extrusion ratios on the microstructure and tensile strength of composites were investigated. The results show that the alignment of Mg2B2O5 whisker along the extrusion direction is improved and the aspect ratio decreases with increasing extrusion ratio, meanwhile, the composites exhibit the best mechanical properties at the extrusion ratio of 25:1. Respectively, the yield strength, the tensile strength and the elongation of the extruded composites is 113.5 MPa, 230 MPa and 7.0%. The tensile strength increases by 37% and 25%, in comparison with the aluminum and composites. According to the analysis of fracture, the ductile failure of 6061Al matrix, the reinforcement fracture and the whisker-matrix interface debonding act as the main mechanism of fracture nucleation.
Key words: Al matrix composites; Mg2B2O5 whisker; hot extrusion; fracture
