嵌入原子法研究Ni3Al中点缺陷以及Re择优占位和集团化

基于纯金属元素Ni，Al和Re的基本物理性质，建立了一个Ni-Al-Re三元体系的分析型嵌入原子多体势.结合分子动力学计算了Ni₃Al的平衡晶格常数、弹性模量、结合能、空位形成能以及反位置缺陷形成能，并分析了Ni₃Al中点缺陷的存在形式.计算结果表明，当成分偏离理想化学配比时出现反位置缺陷.同时研究了Re在Ni₃Al中的择优占位以及Re在Ni₃Al和Ni中的集团化行为.计算结果表明，Re在Ni₃Al中优先置换Al的位置，且发现当Re原子团的尺寸接近于11?时，Re原子团的长大趋势变弱.计算结果与实验以及其他的理论计算结果相符合. 关键词： 嵌入原子势 3Al')" href="#">Ni₃Al Re 占位 集团化     

等离子体氯化氧化法太白反应器流场的数值模拟

本文提出了等离子体氯化氧化法钛白反应器流程的物理化学流体动力学模型,用k-ε方程描述湍流运动,用Partankar-spalaing发展的SIMPLER方法对控制方程求解,就三种情况即a)有化学反应,壁面绝热,b)有化学反应,壁面温度T_w=450k,c)无化学反应,壁面绝热,给出了反应器中的速度场,温度场和浓度分布,对钛白生产的物理化学过程作了数值模拟,所得结果可作为有关工程设计的理论依据。     

Re effects in model Ni-based superalloys investigated with first-principles calculations and atom probe tomography

The phase partition and site preference of Re atoms in a ternary Ni-Al-Re model alloy,including the electronic structure of different Re configurations,are investigated with first-principles calculations and atom probe tomography.The Re distribution of single,nearest neighbor(NN),next-nearest neighbor(NNN),and cluster configurations are respectively designed in the models withγandγphases.The results show that the Re atoms tend to enteringγphase and the Re atoms prefer to occupy the Al sites inγphase.The Re cluster with a combination of NN and NNN Re-Re pair configuration is not preferred than the isolated Re atom in the Ni-based superalloys,and the configuration with isolated Re atom is more preferred in the system.Especially,the electronic states are analyzed and the energetic parameters are calculated.The electronic structure analyses show there exists strong Ni-Re electronic interaction and it is mainly contributed by the d-d hybridization.The characteristic features of the electronic states of the Re doping effects are also given.It is also found that Re atoms prefer the Al sites inγside at the interface.The density of states at or near the Fermi level and the d-d hybridizations of NN Ni-Re are found to be important in the systems.