聶建峰2， Barry C Muddle2
(1. 華南理工大學 機械工程學院，廣州 510641;
2. Department of Materials Engineering,
Monash University, Clayton,
Victoria 3168, Australia)
摘 要: 采用常規(guī)和高分辨電鏡研究了時效AZ91鎂鋁合金中2種形態(tài)γ-Mg17Al12析出相的HCP/BCC相界面結(jié)構(gòu)。 發(fā)現(xiàn)第一類析出相的慣習面 (0002)α ∥{330}γ以及與其對接的另外2組主要晶面的面間錯配度都很小（4%和2%）， 因此界面能較小； 而第2類析出相的慣習面 (011-0)α∥(3-30)γ以及與其對接的另一組主要晶面的面間錯配度都較大（11% 和15%）， 因此界面能較大。 從界面能和相變應變兩方面討論了各類析出相析出密度差別的原因, 提出了改變析出密度、 提高鎂鋁合金時效強化效果的可能途徑。
關(guān)鍵字: AZ91鎂鋁合金； γ-Mg17Al12析出相； HCP/BCC相界面； 透射電鏡分析
WU Dong-xiao1， NIE Jian-feng2， Barry C Muddle2
（1. College of Mechanical Engineering,
South China University of Technology, Guangzhou 510641, China;
2. Department of Materials Engineering,
Monash University, Clayton,Victoria 3168,Australia）
Abstract:The HCP/BCC interphase boundaries between the Mg matrix and γ-Mg17Al12 precipitates for two kinds of precipitates produced in an aged AZ91 Mg-Al alloy were characterized using both conventional and high resolution TEM. It is found that the planar misfit across the (0002)α∥{330}γ habit plane of the first kind of precipitate is very low(<4%), thus forming a low (strain) energy interface, while that across the (011-0)α∥(3-30)γ habit plane of the second kind of precipitate is markedly high(15%), thus producing a high (strain) energy interface. The difference in precipitation density of various kinds of precipitate was interpretted in terms of the interfacial energy, and of the strain induced by the precipitation; and plausible ways of altering the relative densities of the precipitates so as to enhance the precipitation-strengthening effect of the alloy were proposed.
Key words: AZ91 Mg-Al alloy; γ-Mg17Al12 precipitate; HCP/BCC interphase boundary; TEM
