微結(jié)構(gòu)演變的計(jì)算機(jī)模擬
(中南大學(xué) 材料科學(xué)與工程學(xué)院， 長(zhǎng)沙 410083)
摘 要: 采用Monte-Carlo方法模擬了時(shí)效初期Al-4.0Cu-0.3Mg-(0.4Ag)-(0.2Sc)合金的原子分布。研究結(jié)果表明： 在時(shí)效過(guò)程中含微量鈧的Al-Cu-Mg合金中鎂原子逐步向鈧原子周?chē)郏~原子并沒(méi)有向鈧原子周?chē)奂膬A向， 時(shí)效初期出現(xiàn)了大量的Mg/Sc原子團(tuán)簇及Mg/Sc/空位復(fù)合體； 微量鈧的存在促進(jìn)了鎂原子團(tuán)簇化，但抑制了銅原子的團(tuán)簇化； 而含微量銀的合金中鎂原子向銀原子周?chē)鄣膬A向比銅原子大得多， 時(shí)效初期出現(xiàn)了大量的Ag/Mg原子團(tuán)； “Sc/空位”機(jī)制是微量鈧影響Al-Cu-Mg合金時(shí)效初期原子分布與形態(tài)的關(guān)鍵所在。
關(guān)鍵字: Monte-Carlo 方法； 鋁合金； 時(shí)效
microalloyed Al-4.0Cu-0.3Mg alloys
（ School of Materials Science and Engineering,
Central South University, Changsha 410083, China）
Abstract: The Monte-Carlo method was applied to simulate the distribution of solutes in the microalloyed Al-4.0Cu-0.3Mg alloys during the initial ageing stage. The simulation results show that the distribution and morphology of the clusters have been modified by trace element additions, and it is found that one of the key factors governing this effect is Sc/vacancy mechanism. Small additions of Sc to Al-Cu-Mg alloys exhibit a strong tendency to form Mg/Sc cluster and Mg/Sc/vacancy complexes in the atom configurations. The presence of Sc stimulates the clustering of Mg, while depresses the clustering of Cu. A small addition of Ag to Al-Cu-Mg alloys exhibits a strong tendency to form Ag/Mg cluster.
Key words: Monte-Carlo method; aluminium alloys; ageing
