Er对Mo5Si3基合金组织与性能的影响

通过X射线衍射(XRD)、金相显微镜、扫描电镜(SEM)、能谱分析(EDS)及压痕技术研究了Er对Mo5Si3基合金(钼硅质量比5：1)室温组织与性能的影响。研究结果表明：Er的添加导致了三元化合物相Mo3Er2Si4的形成：合金的组织形貌随Er含量不同有所差异，且随Er含量增加，组织中MoSi2相逐渐减少，三元化合物的含量则逐渐增加：过渡族元素Er在MoSi2中不固溶，在Mo5Si3中的溶解度也极小：Er含量为1wt％时得到略高的室温硬度值。Er难以明显改善室温断裂韧性。     

铸态Ti-Sc二元合金的组织特征、相结构和显微硬度

采用真空电弧熔炼技术制备了4种成分的Ti-Sc二元合金,并借助金相显微镜(OM)、扫描电子显微镜(SEM)、能谱分析(EDS)、X射线衍射(XRD)技术及显微硬度测试,对合金的组织形貌、相成分以及不同形貌相的显微硬度进行了分析.结果表明:合金铸态组织形貌为螺旋状、团簇状片层、双相组织;金属Sc对合金的组织有着明显的细化作用,在合金中Sc与Ti形成了固溶体,不同形貌的相,其显微硬度差别较大;当Sc含量为2%～3%时,Ti-Sc二元合金的显微硬度达到最高值,Sc含量高于2%～3%时,合金基体硬度高于片层组织硬度,Sc含量低于2%～3%时,合金基体硬度低于片层组织硬度,少量Sc对合金性能有所提高,对α相片层组织有强化作用.     

Fe73.5 Cu1 Nb3 Si13.5 B9机械合金化纳米晶粉末的特种烧结及磁性能

研究了放电等离子烧结和高压烧结工艺条件对MA Fe73.5Cu1Nb3Si13.5B9纳米晶粉末的烧结块体合金的组织结构与磁性能的影响.结果表明:球磨70 h后,获得了单相a-Fe纳米晶(约9.5 rm)过饱和固溶体粉末;DSC升温曲线中,出现4个不同强度的放热峰,依次发生了纳米晶过饱和固溶体的结构弛豫、非晶晶化以及过饱和固溶体相析出等过程,且相析出过程分两个阶段完成;在p=30 MPa,t=5 min放电等离子烧结(SPS)条件下,当温度达到1 050℃后,可获得相对密度为98.9%、主相为α-Fe的纳米晶(100nm)块体合金,其中,B3=1.34 T,Hc=7.34 kA/m,在p=5.5 GPa,t=5 min条件下,当Pw=1 150 W后,可获得相对密度约99.1%、单相α-Fe纳米晶(21.4 nm)块体合金,其中,Bs=1.14 T,Hc=8.22 kA/m.     

半固态挤压亚微米SiCp/2014复合材料的组织性能研究

通过高能球磨混粉-半固态挤压的方法制备了20％体积分数的亚微米SiC颗粒增强2014铝基复合材料，主要研究了不同挤压温度和挤压比对复合材料组织性能的影响。结果表明，采用适当的半固态挤压温度，控制挤压时复合材料中的液相体积分数为40％左右，或增加挤压比，可以提高亚微米颗粒增强铝基复合材料的室温力学性能。     

Effect of pre-strain on fatigue crack growth of 2E 12 aluminum alloy

The influences of pre-strain on the mechanical property and fatigue crack growth of 2E12 aluminum alloy were evaluated by SEM, TEM, mechanical property and fatigue tests. The axial fatigue tests were conducted under a constant amplitude sinusoidal wave loading at stress ratio of 0.1 in laboratory air and salt fog at room temperature. The results show that the yield stress of pre strain material is higher than that of the material without undergoing pre-strain, but pre-strain can not make the increase of the growth rate of fatigue crack. Fatigue crack growth rates of the alloy in salt fog are higher than those in air. The increased fatigue crack growth of the alloy in a given environment and more brittle striations can be observed in salt fog.     

Influence of Sc on high temperature strengthening behavior of Ti-6A1-4V alloy

Vacuum arc melting technique was used to prepare Ti-6A14V alloy containing Sc （0.3% and 0.5%, mass fraction）. The ingots were melted twice by vacuum self-consumable electrode arc furnace. Forging of ingots was started in β-phase region and finished in high （a＋β-phase region. Annealing after forging was performed in low （a＋β）-phase region for 30 min. Isothermal high temperature compression tests were conducted using thermal simulation machine under Ar atmosphere at 850℃ and 1 000 ℃, and the strain rate were 0.001, 0.01, 0.1 and 1.0 s^-1. Optical microscope（OM）, scanning electron microscopy（SEM）, energy dispersive spectrum（EDS） and transmission electron microscope（TEM） were used to study the microstructure evolution during high temperature deformation. The results show that, the peak stress value of alloys increases with increasing Sc content after deformation at 850℃, however, there is no obvious strengthening of Sc when the alloys are deformed at 1 000 ~C. Sc exists as Sc203 forms by internal oxidation during forging procedure, only minor Sc solutes in matrix. At 850 ~C, the interaction between dislocation and participated particles and twinning mechanism controls the deformation procedure accompanied recrystallization. At 1 000 ℃, the deformation of alloys containing Sc is mainly controlled by twinning, while the deformation of alloy without Sc is not only controlled by twinning, but also the interaction between dislocation and precipitated particles inside the twinning lamellar.     

Sc对Ti-Al二元合金组织与显微硬度的影响

采用真空电弧熔炼技术制备了Ti-6Al、Ti-3Al-35c、Ti-10Al以及Ti-8Al-2Sc四种成分的合金，借助X射线衍射技：术(XRD)对铸态合金的相组成进行了分析。将铸态合金分别在β相区、α＋β相区和仅相区的温度下进行真空等温退火10h并进行水冷。借助光学金相显微镜对合金在不同退火态下的组织进行了分析，并用岛津显微硬度计测量了合金的显微硬度。试验结果表明，铸态Ti-Al-(Se)合金的显微组织形貌主要为魏氏组织、双态组织和网篮组织，其主要析出相为Ti-Al和Al3Sc。金属sc的加入明显细化了合金的组织，同时提高了合金中α片层组织的显微硬度。从金属Sc对合金的组织演变的影响上来看，金属Sc的加入具有稳定仅相的作用。经过等温退火处理后的合金其显微硬度高于铸态合金的显微硬度，Al的含量以及金属Sc的添加均对合金基体和片层组织的硬度产生了一定的影响。     

Chemical pretreatments at surface of WC—6% Cof for diamond coatings

The WC-6% Co(mass fraction)substrate surfaces were chemically pretreated with the two-step etching method,using Murakami reagent for 3-7min,and then an ψ（HNO3):ψ（HCl)=4:1 soluton for 1-15min,Diamond films were deposited on the substrates by a hot-filament chemical vapor deposition reactor.The results show that the Co content of the substrate surfaces can be reduced from 6% to 0.12% within the etching depth of 5-10μm ,the surface roughness of the substrates is increasesd up to Ra=1.0μm,as well as th substrates hardness is decresased from HRA 89..to HRA 84.2 after the two-step etching,A slight preference towarde {111} orientation can be observed from the XRD patterns and SEM micrograph of diamond film on WC-6%Co sample.The morphology of small rice-like ballas diamond was observed on the WC－6％Co substrates.A typical Raman spectrum with a sharp peak at 1332cm^-1 for the diamond film indicates that the deposited films are good-quality polycrystalline diamond.The indentation testing shows that the adhesion between diamond film and the substrate after HF CVD deposition is good.     

纳米晶掺Ce硬质合金粉末的制备

采用高能球磨法，制备出了晶粒度约11nm的掺Ce硬质合金粉末。用XRD、SEM和DTA等分析检测手段，研究了高能球磨过程中，掺Ce硬质合金粉末的结构、形貌和相的变化。结果表明：微量Ce的加入，有利于硬质合金粉末晶粒的细化；高能球磨10小时，即可获得晶粒度为30nm的掺Ce硬质合金粉末；高能球磨20小时，Co相的X-ray衍射峰消失，说明Co相已完全固溶或亚固溶于WC相中；高能球磨30小时，可获得晶粒度的11nm的掺Ce硬质合金粉末。DTA分析表明，与高能球磨前的粉末相比，在300－600℃加热时，高能球磨掺Ce硬质合金粉末出现了明显的结构驰豫。     

准晶体的研究及其进展

准晶体是八十年代中发现的一种新结构物质,木文扼要地介绍了准晶体的发现过程。它的结构特点和结构模型以及相应的理论。它的制备方法和形成条件,探讨了它的稳定性各项物理性能和形成缺陷问题,最后还提出了对今后发展趋势的看法。