含Nd镁铝合金电子结构计算与强化机制分析  

Calculation of Valence Electron Structures and Analysis of Strenghening Mechanism in Mg-Al-Nd Alloy

作　　者：张伟[1] 刘伟东[2] 王彦春[1] 张寿庭[1] 

机构地区：[1]中国地质大学(北京)地质过程与矿产资源国家重点实验室和地下信息探测技术与仪器教育部重点实验室,北京100083 [2]辽宁工业大学材料与化学工程学院,辽宁锦州121001

出　　处：《材料工程》2008年第5期7-12,共6页Journal of Materials Engineering

基　　金：地质过程与矿产资源国家重点实验室基金;国家地质调查局资助项目(200110200009);教育部科学技术研究重点资助项目(104037);教育部博士点资助基金(20010491007)

摘　　要：基于EET理论,计算了Nd元素加入Mg-Al合金后形成的Mg-Al-Nd固溶体,第二相Al2Nd,Al3Nd价电子结构,研究了价电子结构与合金固溶强化、第二相强化、高温稳定性和晶粒细化的关系。Mg-Al-Nd最强键共价电子对数nA值和共价电子密度ρVC值均大于α-Mg的nA值和ρVC值,表明Nd的固溶有利于基体强度的提高;第二相Al2Nd最强键(nA=0.44396)与Al3Nd最强键(nA=0.38949)的键合强度均远大于基体α-Mg(nA=0.11199)的键合强度,因此,Al2Nd和Al3Nd极大地阻碍了位错的运动,提高了合金的强度;Al2Nd和Al3Nd的单位体积成键能力FV值分别为145.91和242.35,与γ-Mg17Al12(FγV-Mg17 Al12=44.22)相比较,它们的高温稳定性更好,其存在有利于改善Mg-Al合金的高温性能;Nd提高了液态合金中邻近原子间键合强度,增加了基体的形核率,减缓了晶粒长大速度,进而细化了晶粒,提高了合金的力学性能。The valence electron structures of Mg-Al-Nd solid solution phase,sencond phase Al2Nd and Al3Nd were calculated based on the Empirical Electron Theory of solids and molecules（EET）, and the relationship between valence electron structures and the alloy solid solution strengthen, sencond phase strengthen, high temperature stability, grain refinement was studied. The valence electron pairs on the strongest bond nn value and covalent electron density ρv^C value of Mg-Al-Nd were bigger than that of α-Mg, which indicated the solid solution of Nd element was advantageous to the substrate intensity enhancement; The strongest bond of Al2Nd（nA=0. 44396） and Al3Nd（nA=0. 38949） were far bigger than that of substrate α-Mg（nA = 0. 11199）, therefore, Al2Nd enormously hinden the dislocation movement, enhanced the alloy intensity; Compared the Fv value of γ-Mg17 Al12 （Fv^γMg17Al12 =44.22）, the total bond-forming ability in unit volume Fv value of Al2Nd and Al3Nd respectively was 145. 91 and 242.35, which showed that their high temperature stability was better and their existence was advantageous to improves the high temperature performance of Mg-Al alloy; Nd enhanced bonding strength of atoms neighbored to it in the liquid state alloy, increased the substrate＇s nucleation rate, slowed down the crystal growth speed, then refined the grain size, enhanced the mechanics performance.

关 键 词：Al2Nd Al3Nd MG-AL合金 价电子结构 力学性能 

分 类 号：TG146.22[一般工业技术—材料科学与工程] TG146.454[金属学及工艺—金属材料]