Ca对AZ4.51变形镁合金组织和性能的影响

采用AZ4.51变形镁合金经均匀化处理和热轧后得到的厚度为1 mm的薄带.用光学显微镜(OM)、扫描电子显微镜(SEM)和电子万能试验机等对不含钙和钙含量为0.3%的镁合金薄带进行组织分析和性能测试.研究发现,Ca的加入改善了镁合金组织的均匀性,从而改善了合金力学性能的各向异性,使材料在不同方向上的强度和伸长率差别减小,尤其提高了材料在与轧制方向成45°方向上的力学性能,其轧制态的抗拉强度为292.7 MPa,屈服强度为200.1 MPa,伸长率为9.2%,分别提高了25.25%、43.75%和24.32%.同时Ca的加入提高了材料的变形能力,使镁合金在350 ℃轧制(每道次压下量设定为50%)时的一次压下量达到33.8%,提高了10%.     

运动员专业素质测试方法研究与系统开发

根据现有运动员专业素质测试方面只用脉搏测试仪所存在的弊端，我们通过对运动员各个方面的综合素质进行综合分析，改进脉搏测试方法，并应用数学建模方法建立模型，最后开发出软件和硬件，打造一个科学合理的系统帮助运动员和教练进行分析并不断发现和改正运动员在训练过程中所存在的不足和缺陷，最终帮运动员提高成绩。     

网址导航系统运行速度的改进研究

自从hao123网址导航系统出现以后，各种各样的网址导航系统层出不穷，虽然表面上看起来都没有什么差别，但其使用速度确是千差万别。针对这个问题，本文分别在搜索引擎设计和代码结构设计上进行改进并开发出了相应的网址导航系统——118网址导航系统，通过对该系统的开发与实现过程的介绍，详细地阐述了网址导航系统改进的方法和改进后的效果。     

反应合成法制备Mg-Li基复合材料的热力学研究

反应合成法制备ＭｇＬｉ基复合材料的热力学研究于化顺闵光辉王大庆（山东工业大学，济南２５００６１）（山东师范大学）陈熙琛（中国科学院物理研究所）关键词：ＭｇＬｉ合金自生复合材料反应合成法１引言ＭｇＬｉ基复合材料具有较小的密度、较高的比强度和比刚...     

含铝蠕铁的研究

对稀土及稀土镁处理含铝蠕铁进行了研究。结果表明：含铝铸铁的蠕化范围比普通铸铁的大得多，并对其机理进行了探讨。     

高强度导电铜基复合材料

高强度导电铜基复合材料是一类很有应用潜力的功能材料，本文综述了该类材料的国内外研究现状，并对其设计原理，制备工艺及性能进行了介绍，最后阐述了该类材料的发展方向。     

Cu—Zr基体中Al—Ti—B2O3体系的反应热力学研究

为研究ＴｉＢ２／ＣｕＺｒ 复合材料的增强相在ＣｕＺｒ 基体中形成的热力学条件, 采用ＤＴＡ 分析和不同温度下的热爆试验, 研究了ＡｌＴｉＢ２Ｏ３ 体系的反应热力学行为, 并讨论了其反应合成机制。结果表明： 在１１００℃下, 该体系能自动发生反应, 生成产物为ＴｉＢ２ 和少量Ａｌ２Ｏ３ ; 在较低温度反应时, 产物中存在硼化物过渡相。基于热爆工艺参数, 在ＣｕＺｒ 熔体中制备了ＴｉＢ２／ＣｕＺｒ 复合材料。     

Martensitic transformation and mechanical properties of Ti-rich Ti-Ni-Cu melt-spun ribbon

Martensitic transformation, mechanical and thermomechanical properties of a Ti-rich Ti₅₂Ni₂₃Cu₂₅ melt spun ribbon annealed at a temperature below the crystallization temperature were studied by XRD, DSC and DMA. After annealing the initially amorphous ribbon at 400 °C for 10 h, the ribbon is fully crystallized and exhibits one-stage B2?B19 phase transformation with the temperature hysteresis of 14 °C. The annealed ribbon is composed of B2, B19 and B11-TiCu phase with (001) preferential orientation. On the stress―strain curves, the rearrangement of the martensite variants and stress-induced martensitic transformation are observed below the M_f temperature and above the A_f temperature, respectively. The annealed ribbon exhibits up to 1.6% superelastic shape recovery with small stress hysteresis of 25 MPa. No flat stress-plateau is associated with the superelasticity. The annealed ribbon shows a well-defined shape memory effect during thermal cycling from ?60 to 100 °C. The transformation strain and recovery strain increase with increasing the applied external stress. Under the external stress above 150 MPa, the shape recovery strain is not sensitive to it and keeps stable at about 1.74%.     

Dependence of characteristics of LaB6 films on DC magnetron sputtering power

Lanthanum hexaboride(LaB₆) thin films were deposited on glass substrate by DC magnetron sputtering technology, and the AFM, XRD and scratch tests were used to characterize the deposited films. Influences of sputtering power on the microstructure and the bonding strength between the film and substrate were investigated. AFM observation proves that the dense films are obtained, and the surface roughness is below 4.3 nm. The LaB₆ film shows the crystalline structure with the grain less than 100 nm. The XRD pattern identifies that the crystal structure of the films is in accordance with that of bulk LaB₆, and the (100) crystal face is dominated. The average grain size decreases firstly and then increases with increasing power, and reaches the minimum of 40 nm when the sputtering power is 44 W. Moreover, the intensity of peaks in XRD pattern increases firstly and decreases afterward with increasing power. When the sputtering power is 50 W, the peak intensity reaches the maximum, showing an intense relationship between the power and crystal structures. The scratch test shows that interface bonding strength of the film/substrate is higher at the power of 44 W than the others, due to the formation of the nanosized crystals and their improved surface energy.     

铸造Al—Li—Cu合金的组合与性能

本文对Al－Li－Cu三元系铸造合金的组织、性能与成分设计进行了研究。研究发现,Al－Li－Cu三元系铸造合金组织粗大,在枝晶间有大量的Cu偏析;粗大的组织严重损害合金的韧性,在时效态,Al－3Li－Cu三元合金的力学性能较高,但申长较低（0．4％）,采用双级时效时,伸长率可达1％。