(1. 中南大學(xué) 材料科學(xué)與工程學(xué)院，長(zhǎng)沙 410083；
2. Department of Chemical and Materials Engineering, University of Kentucky, Lerington, KY40506, USA)
摘 要: 通過四點(diǎn)彎曲疲勞試驗(yàn)研究2524−T34板材的疲勞性能，借助金相和掃描電鏡觀察疲勞裂紋的萌生和擴(kuò)展行為。結(jié)果表明：2524合金具有良好的疲勞性能，疲勞強(qiáng)度達(dá)到屈服強(qiáng)度的80%以上；疲勞裂紋主要在第二相粒子以及第二相粒子/基體界面萌生，裂紋擴(kuò)展過程中的偏轉(zhuǎn)與晶界的阻礙有關(guān)；相鄰晶粒內(nèi)兩個(gè)有利滑移面之間的位向差是控制裂紋通過晶界擴(kuò)展的重要因素。
關(guān)鍵字: 2524合金；疲勞裂紋；萌生；擴(kuò)展；顯微組織
（1. School of Materials Science and Engineering, Central South University, Changsha 410083,China;
2. Department of Chemical and Materials Engineering, University of Kentucky, Lerington, KY40506, USA）
Abstract:The fatigue performance of 2524−T34 sheets was studied by four-point bend fatigue test. The fatigue crack initiation and propagation behavior were observed by optical microscopy and scanning electron microscopy. The results indicate that 2524 alloy shows superior fatigue properties. The fatigue strength is up to 80% of the yield strength. The fatigue crack mainly initiates from the second phase particles and the interface between the second phase particles and matrix. The crack plane deflection in the process of crack propagation relates to the resistance of the grain boundary. The difference of crystallographic orientation between the two favoured slip planes within the two neighboring grains is an important factor to control crack propagation across a grain boundary.
Key words: 2524 alloy; fatigue crack; initiation; propagation; microstructure
