Anisotropic and temperature-dependent growth mechanism of S-phase precipitates in Al-Cu-Mg alloy in relation with GPB zones  

温度作用下与GPB区相关的Al-Cu-Mg合金中S相的各向异性生长机制（英文）

作　　者：尹美杰[1] 陈江华[1] 王双宝[1] 刘自然[1] 茶丽梅[1] 段石云 伍翠兰[1] 

机构地区：[1]湖南大学材料科学与工程学院,长沙410082

出　　处：《Transactions of Nonferrous Metals Society of China》2016年第1期1-11,共11页中国有色金属学报（英文版）

基　　金：Projects(51371081,11427806,51471067,51171063) supported by the National Natural Science Foundation of China;Project(2009CB623704) supported by the National Basic Research Program of China

摘　　要：By employing atomic-resolution imaging and first principles energy calculations, the growth behavior of S-phase precipitates in a high strength A1-Cu-Mg alloy was investigated. It is demonstrated that the nucleation and growth of the S-phase precipitate are rather anisotropic and temperature-dependent companying with low dimensional phase transformation. There are actually two types of Guinier-Preston （GP） zones that determine the formation mechanism of S-phase at high aging temperatures higher than 180 ℃. One is the precursors of the S-phase itself, the other is the structural units or the precursors of the well-known Guinier-Preston-Bagaryatsky （GPB） zones. At high temperatures the later GPB zone units may form around S-phase precipitate and cease its growth in the width direction, leading to the formation of rod-like S-phase crystals; whereas at low temperatures the S-phase precipitates develop without the interference with GPB zones, resulting in S-phase orecioitates with lath-like momhology.采用原子分辨率成像和第一性原理计算,研究S析出相颗粒在高强Al-Cu-Mg合金晶粒内部的生长行为。结果表明,S相的形核和生长具有很强的各向异性特征和受温度影响的特征,同时伴随低维相转变。事实上,在较高的时效温度下(高于180°C),存在两种特征的GP区,它们决定S相晶体的生长机制。一种是S相本身的前驱体相,另一种是Guinier–Preston–Bagaryatsky(GPB)区的结构单元或其前驱体相。在较高温度下,GPB区的结构单元会在S相周围形成,并阻碍S相沿宽度方向的生长,导致S相长成柱状晶体;而在低温下,S相的生长不受GPB区的干扰,形成板条状形貌。

关 键 词：aluminum alloy precipitation age hardening ANISOTROPY crystal growth 

分 类 号：TG146.21[一般工业技术—材料科学与工程]