首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 99 毫秒
1.
Au—Cu合金的微观结构和性质   总被引:1,自引:0,他引:1  
谢佑卿  张晓东 《金属学报》1994,30(12):A531-A539
依据建立在统计热力学和金属电子理论基础上的合金综合理论-合金相的特征晶体理论,对Au-Cu合金的微观结构和性质进行了研究,确定了特征性质(势能和体积)的相互作用方程,各特征原子的电子结构及演变特点;计算了合金的形成热,混合Gibbs自由能和晶格常数随成分的变化,这些性质的理论值和实验值符合很好。  相似文献   

2.
谢佑卿 《金属学报》1998,34(12):1233-1242
依据合金特征晶体理论,固溶体中组元的原子状态分裂成若干特征原子状态,固溶体的晶格常数可由特征晶体的晶格常数相加定律,特征原子体积相加定律的特征原子状态相加定律求得,介绍了无序二元固溶体的9种晶格常数函数;确定了无序Au-Cu合金及其元的晶格常数函数;预计了Au3Cu,AuCu,AuCu3和相应有序合金随成分变化的晶格常数。理论值与实验符合较好。  相似文献   

3.
高强度、高电导率双相Cu-Ag合金   总被引:4,自引:2,他引:2  
运用加工和热处理方法使Cu-Nb合金和Cu-Ag合金具有均匀细微的双相纤维组织,其电导率高达80%IACS(ρ=2.15μΩ.cm)强度高达1GPa以上,文中介绍了MMSc双相Cu合金的组织特征及变形程度,热处理制度对Cu-Nb合金和Cu-Ag合金的纤维组织,电导率,强度的影响。  相似文献   

4.
基于密度泛函理论并采用总体能量法,对2c和3g位Ni分别被Co取代后的LaNi4Co储氢合金进行了电子结构分析,计算了LaNi5优化几何结构及其结构参数与性质,该方法可为该类合金的结构预测提供理论依据。并对LaNi4Co的总体能量和电子态密度进行了分析。根据计算结果,分析了LaNi4Co的电子结构,及Co取代前后合金中电子结构的变化。  相似文献   

5.
用实验方法研究了Cu-Pd系中的Cu-16.67Pd和Cu-37.5Pd合金的性能与结构,发现合金性能反常。在长时间热处理后形成四方晶体的Cu5Pd有序化合物及体心立方β相,但未证实Cu5Pd3的存在。  相似文献   

6.
Mg,Cu及时效对ZA27合金组织和腐蚀特性的影响   总被引:2,自引:1,他引:1  
研究合金元素Mg和Cu及时效处理时间及ZA27合金的组织和腐蚀特性的影响。研究发现,元素Mg,Cu和时效处理对合金的组织转变有大影响,Mg抑制α和β相的固相转变,而Cu促进α和β相的固态转变,从而影响合金的腐蚀特性。根据盐雾腐蚀试验结果结合组织特征得出:ZA27合金中Mg和Cu的合适加入量分别为0.03%-0.20%Mg,0.5%-2.5%Cu,最佳时效处理时间为2h适宜。  相似文献   

7.
凌刚  季雨  胡小军  邬秋林  褚维  杨国斌  王润 《金属学报》1995,31(20):353-359
本文利用透射电子显微学和能谱分析技术研究了FeZrB(Cu)非晶合金在动态升温过程中和不同热处理温度下微观结构的变化.研究发现,在合金晶化过程中,非晶相由富Zr和富Fe区组成.富Zr相对bccFe相的析出和稳定性有着重要的影响.α-Zr相的析出是bccFe相开始失稳长大的标志.  相似文献   

8.
依据特征晶体理论(CC)确定Pt-Ru合金系中的特征原子序列和特征晶体序列的电子结构、势能、原子体积、晶格常数和结合能等,研究合金催化剂的稳定性、催化性能及成分配比;计算Pt-Ru有序合金中Pt和Ru配比分别为3-1、1-1和1-3的合金的势能和晶格常数,并分析组元Pt的组态变化;计算Pt-Ru无序合金的平均性质和组元Pt的电子结构.研究结果表明:随着Ru含量的增加,势能降低,合金稳定性增强,晶格常数随之减小,组元Pt的d空穴增加,提高了催化活性;合金中Pt与Ru的最佳原子个数之比约为1-1.  相似文献   

9.
柴惠芬  阮征 《金属学报》1994,30(11):A502-A506
观察了两种不同滑移方式的材料──纯Cu及Cu-Zn合金经预变形及循环软化后的表面滑移线形貌.发现二者预变形的双交滑移特征不同,且Cu-Zn合金的交滑移与应力—应变曲线上的动态应变时效现象相对应.Cu-Zn合金循环软化后有两种衬度的滑移带,而纯Cu则主要表现为驻留滑移带,说明两种材料疲劳应变的容纳方式不同.根据滑移带形貌解释了它们不同的软化行为.  相似文献   

10.
柴惠芬  阮征  范群成 《金属学报》1994,30(11):502-506
观察了两种不同滑移方式的材料──纯Cu及Cu-Zn合金经预变形及循环软化后的表面滑移线形貌.发现二者预变形的双交滑移特征不同,且Cu-Zn合金的交滑移与应力—应变曲线上的动态应变时效现象相对应.Cu-Zn合金循环软化后有两种衬度的滑移带,而纯Cu则主要表现为驻留滑移带,说明两种材料疲劳应变的容纳方式不同.根据滑移带形貌解释了它们不同的软化行为.  相似文献   

11.
Electronic structure of Au-Cu alloys   总被引:2,自引:0,他引:2  
By studying the correlativity between energy, volume and electronic structure of characteristic crystals and bound conditions of OA theory, the potential energy function, atomic volume interactive function and electronic structure of Au-Cu alloys have been determined. Then following the general Vegard‘s law in characteristic theory, the electronic structure and properties of disordered continue solid solution and three ordered alloys with the maximum ordering degree are calculated. It is found that the non-bonding electrons and near-free electrons in outer shell will transform to covalent electrons during alloying. By analyzing the variation of electronic structure and cohesion of ordering and disordered alloys, the transformation of order-disorder transition Au-Cu alloy has been studied.  相似文献   

12.
Misfit strain energy has been calculated for the AuCu lattice from interatomic distances and the Morse function; the calculations give results of the same order of magnitude as calculations from elasticity theory. It is shown that electronic rearrangements occur during uniaxial tension, greatly reducing the strain energy from that calculated by ordinary methods. The theory of Pauling is applied and the electronic rearrangements derived from this theory reduce the strain energy to small values. This is not true, however, in other lattices. An explanation is advanced as to why Au-Cu alloys form more exothermically than Au-Ag alloys.  相似文献   

13.
李日升 《金属学报》1987,23(4):253-261
本文介绍了新近关于合金择优溅射机制的一个新观点.这个观点认为,在AuCu合金中所观测到的择优溅射现象,主要是离子轰击诱发的Gibbs偏析的结果;只有当轰击离子的能量低至几百电子伏、接近溅射的“准阈能”值对,质量效应才起明显的作用。  相似文献   

14.
采用密度泛函理论(DFT)中的BLYP和ROBLYP交换.相关泛函,基于YBa2Cu3O7单晶胞即39个原子组成的团簇模型,计算了其能隙、磁化系数、电子比热及比热系数随温度的变化关系,并分析了在不同温度下其最高占据态的分子轨道图。结果表明,YBa2Cu3O7存在3个特征温度Tc、T^*和T^0,在正常态存在赝能隙,并且其超导能隙和赝能隙均具有d波对称性。  相似文献   

15.
The valence bond structure of substitutional BCC based Ta-W alloys is studied using characteristic crystal(CC)theory.This theory is based on cluster statistics of random alloys.By studying the correlativity between energy and volume of the CC in Ta-W alloys,the valence bond structure of CC is determined by the energy and shape method.Then,following additive law of CC,the valence bond structure of Ta-W alloys is calculated.It is found that the outer shell valence electronic distribution of Ta-W alloys shows ...  相似文献   

16.
Order-N calculations of the electronic states of models of random substitutional Cu-Zn alloys have been carried out. By analyzing the results, new general features that are characteristic of the Coulomb energies of alloys have been discovered. This article shows how they compare with other models of alloys that have been discussed in the literature. The most important consequence of these calculations is the new insight that they give into the nature of the Coulomb energy in the density functional theory.  相似文献   

17.
介绍了金基合金的强化方式以及 Au-Cu 合金的强化特点,特别是添加元素对 Au-Cu 合金的有序化转变和时效硬化等的影响。探讨了Au-Cu系多元合金的各方面性能、应用及其最新的研究情况。  相似文献   

18.
lINTRODUCTIONInrecentyearslthePau1ing'svaIenceb0nd(VB)the0ryhasmadeagreatprogressinChi-m.First,YtidevelopedthePauling'svalencebondtheoryandestablishedtheEETtheory[']landthenbasedontheenergy-b0ndthe0ryandEETtheory,Xieproducedtheone-atom-statetheory['1(OAtheory)ofpuremetalswiththeunityof"shape"and"energy"andthendevel-opedthecentralat0msmodelinthestatisticthermodynamicsandbuiltthecharacteristiccrys-talthe0ry(CCtheory)[31.NowtheOAtheoryhasmadeanewprogressandcanbeappliedto-intermetallic…  相似文献   

19.
Au-Cu bimetallic nanoparticles with uniform size,shape,and compositions were synthesized by wet chemistry method,and then the Au-Cu/SiO_2 catalyst supported on SiO_2 was prepared.Meanwhile,their catalytic activity for the selective oxidation of propene to acrolein using O_2 as an oxidant was evaluated.The bimetallic catalyst shows a significantly enhanced catalytic performance comparing with Au and Cu monometallic catalysts.Characterization of the materials and kinetic study was conducted to explore the cooperating mechanism of Au and Cu for improving the catalytic activity of the bimetallic catalyst.Cu component can segregate to the alloy surface and the Au-Cu alloy transferred to Au-CuO core/shell structure after annealing during the preparation process.Based on the Mars-van Krevelen mechanism for the selective oxidation of propene over the prepared catalysts,the coexistence of CuO can promote the adsorption and activation of O_2.Meanwhile,the electrons transfer from Au to Cu in the catalyst can facilitate the adsorptions of both oxygen on CuO sites and propene on Au sites.The combined effects of the above two aspects result in the high catalytic activity of the Au-Cu/SiO_2 catalyst for selective oxidation of propene to acrolein,compared to the Au/SiO_2 and CuO/SiO_2 catalysts.  相似文献   

20.
采用第一性原理方法分析了Ag(110)、(211)与Ni(110)、(211)的界面结合情况。通过对界面结合能、电荷布居以及界面处的电子结构等研究分析发现,在Ag与Ni界面的结合形式中,以Ag(110)/Ni(211)的界面结合能最高,界面处的电子杂化最为剧烈,其界面结合也是最稳定的  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号