(1. 中南大學(xué) 材料科學(xué)與工程學(xué)院，長(zhǎng)沙410083；
2. 東北輕合金有限責(zé)任公司，哈爾濱150060)
摘 要: 采用拉伸和疲勞力學(xué)性能測(cè)試、金相和透射電子顯微分析，研究2524和用微量Sc和Zr合金化的2524SZ合金T3態(tài)薄板的組織和性能，考察微量Sc和Zr合金化對(duì)2524SZ合金T3態(tài)薄板疲勞裂紋擴(kuò)展特性的影響。結(jié)果表明：微量Sc和Zr在2524SZ合金中主要以次生的Al3(Sc, Zr)粒子形式存在，這種粒子與基體共格，固溶處理過(guò)程中能部分抑制合金的再結(jié)晶，基體晶粒組織主要由細(xì)小的亞晶組成；在相近的應(yīng)力強(qiáng)度因子ΔK條件下，2524和2524SZ合金T3態(tài)薄板的疲勞裂紋擴(kuò)展速率分別為4.50和2.35 μm/ cycle，表明添加微量Sc和Zr能顯著降低 2524SZ合金抵抗疲勞裂紋擴(kuò)展速率；亞晶強(qiáng)化和Al3(Sc, Zr)相析出強(qiáng)化是微量Sc和Zr使2524SZ合金疲勞裂紋擴(kuò)展速率降低的主要原因。
關(guān)鍵字: 2524SZ合金；Sc；Zr；亞晶；Al3(Sc, Zr)析出相；疲勞裂紋；擴(kuò)展特性
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Northeast Light Alloy Co. Ltd, Harbin 150060, China）
Abstract:The microstructures and properties of 2524-T3 alloy sheet and 2524SZ-T3 alloy sheet with minor Sc and Zr, were investigated by tensile test, OM and TEM analysis. The effects of minor Sc and Zr on the fatigue crack development characteristics of 2524SZ alloy sheet were studied. The results show that in 2524SZ aluminum alloy, minor Sc and Zr exist as secondary Al3(Sc, Zr) precipitates，which can partly prohibit recrystallization, and the matrix mainly consists of subgrain. At the similar ΔK value, the fatigue crack propagation rates of 2524 and 2524SZ alloy sheets are 4.50 and 2.35 μm/cycle, respectively, showing that minor Sc and Zr can obviously decrease the fatigue crack propagation velocity. Subgrain structure and Al3(Sc, Zr) precipitates are responsible for the decrease of the fatigue crack propagation velocity of 2524SZ alloy.
Key words: 2524SZ alloy; scandium; zirconium; subgrain structure; Al3(Sc, Zr) precipitate; fatigue crack; propagation characteristics
