微屈服行為的影響
(1.北京有色金屬研究總院國家金屬復(fù)合材料工程技術(shù)研究中心，北京 100088;
2.哈爾濱工業(yè)大學(xué)材料學(xué)院， 哈爾濱 150001)
摘 要: 采用微屈服強(qiáng)度測試、 透射電鏡和高分辨透射電鏡分析，對經(jīng)過不同冷熱循環(huán)工藝處理后的顆粒增強(qiáng)鋁基復(fù)合材料的微屈服行為進(jìn)行了研究。結(jié)果表明，冷熱循環(huán)次數(shù)雖然對顆粒增強(qiáng)鋁基復(fù)合材料微屈服行為的宏觀規(guī)律沒有本質(zhì)的影響，但是仍然影響顆粒增強(qiáng)鋁基復(fù)合材料的微屈服行為。 對球形顆粒而言， 小應(yīng)變量下的微屈服強(qiáng)度隨冷熱循環(huán)次數(shù)的增加而增高；但對棱形顆粒而言， 循環(huán)次數(shù)的影響較為復(fù)雜。 研究還表明， 冷熱循環(huán)次數(shù)影響顆粒增強(qiáng)鋁基復(fù)合材料微屈服行為的主要原因是其位錯組態(tài)和殘余應(yīng)力在不同的循環(huán)次數(shù)下有明顯的不同。
關(guān)鍵字: 關(guān)鍵詞:顆粒增強(qiáng)鋁基復(fù)合材料 微屈服行為 冷熱循環(huán)處理
（General Research Institute for Nonferrous Metals, Beijing 100088, P. R. China
School of Materials Science and Engineering,Harbin Institute of Technology, Harbin 150001, P. R. China）
Abstract:An aluminum alloy(6061) matrix composite reinforced with 35% volume fraction of Al2O3 particles or SiC was fabricated by squeeze casting method. The Al2O3 particles are spherical, and SiC particles are angular. The microyield behavior of the composite was investigated, and the effect of different thermal cycling treatments on the microyield behaviors of the composite was studied. Based on TEM and HREM observations of microstructures, the mechanism of microyield behavior in the Al2O3p/6061 or SiCp/6061 composites was analyzed. Results indicate that the microyield behavior of the particles reinforced aluminum matrix composites can be described by Brown-Lukens's theory which satisfactorily explained that of aluminium alloys and other light alloys, and is greatly affected by the different thermal cycling treatments. The more the numbers of thermal cycling treatments, the higher the microyield strength at small strains in the Al2O3p/6061. Thermal cycling treatment mainly affects the thermal mismatch stress and the density of movable dislocations in the matrix.
Key words: Al matrix composites microyield behavior thermal cycling treatment
