核电压力容器SA508-3钢内部裂纹高温焊合实验

裂纹缺陷严重影响大型锻件的合格率及使用寿命。为保证核电大型锻件质量、提高核电压力容器安全性,以加热温度、下压量以及保压时间为参数,采用预置裂纹方式对核电压力容器用钢SA508-3进行内部裂纹高温焊合实验研究。裂纹焊合效果采用金相显微镜、扫描电镜、能谱分析及力学性能实验等进行评价。结果显示,在高温短时间小变形情况下SA508-3材料内部裂纹均能焊合,裂纹焊合最低条件为:加热温度1100℃,变形量10%,保压时间15 s;焊合后试样强度值与基体相似,但塑性值有较大波动;根据扫描电镜及能谱分析确定,试样连接过程中带入的大量夹杂物是材料塑性指标波动较大的主要原因。     

热处理工艺对Heusler型Ni2MnGa合金马氏体相变的影响

采用电弧熔炼法熔炼Ni48Mn31Ga21和Ni50Mn255Ga25两种合金,并对这两种合金进行了热处理,借助交流磁化率测定、金相显微镜观察、X射线衍射等手段研究了热处理工艺条件对非化学计量比的Ni48Mn31Ga21合金马氏体相变和结构有序度的影响.结果表明(1)Ni48Mn31Ga21合金相变特征温度为Ms=305K,Mf=297K,As=313K,Af=318K,居里温度Tc=366K;(2)与空冷态相比,淬火态的马氏体转变量降低,经过400℃退火后,随着保温时间t的延长,马氏体转变量上升,当t=50h时达到最大值;(3)Ni48Mn31Ga21合金经过900℃×4d+400℃×50h热处理后,有序度明显提高.     

Mo—La2O3烧结坯间隙杂质的研究

通过扫描电镜（ＳＥＭ）、电子探针（ＥＰＭＡ）、Ｘ射线衍射（ＸＲＤ）及俄歇电子能谱（ＡＥＳ）研究了Ｍｏ－Ｌａ２Ｏ３烧结坯中的间隙杂质。结果表明：Ｌａ２Ｏ３的加入提高了烧结睛坯的抗弯强度和韧性。间隙杂质不驻存在于Ｍｏ中,而且在Ｌａ２Ｏ３粒子表面吸附,使晶界杂质浓度降低。     

周期反向电流法高电流密度电解精炼铜的研究

模拟铜电解精炼工业生产条件,在小型电解中研究周期反向电流法高流密度电解精炼铜的可行性。并用XRD、SEM及离子体发射光谱研究杂质对铜沉积的结构和组成的影响。研究表明：当电流密度为400A.m^2－,电流周期阴极沉积时间75s溶解时间1．5s,添加剂用量（g.dm^-3）;硫脲0．010、骨胶0．010、Cl^-0．050,有害杂质含量（g.dm^-3):As(V)≤3．0、Sb（Ⅲ）≤0．14、Bi（Ⅲ）≤0．1时能获得表面光滑平整纯度为99．99％的电解铜。以400A.m^-2的周期反向电流电解时,铜沉积的电结晶生长形态为脊状＋块状,晶面择优取向为（220）,少量杂质存在对铜沉积结构有一定影响。     

纯净钢生产技术及现状

本文简述了近年来国外主要炼钢厂生产纯净钢钢中杂质元素控制技术的发展，系统分析了钢中氧、碳、氮、硫、磷、氢等元素在钢中行为和降低杂质元素的措施。     

Evaluation of the relative γ-ray intensities emitted from ^56Co and ^66Ga

~(56)Co and ~(66)Ga with γ-ray energies covering the range of 0.84-3.55 and 0.68-4.81MeV, respectively, are important radionuclides for Ge detector calibration. The newly evaluated relative γ-ray intensities were recommended using the measurements finished after 2000 year by Baglin and Browne in 2004. In 2005 China groups measured the relative γ-ray intensities. The China measurements were about 2% systematically lower than other measurements and these evaluations. In this paper the discrepancies among these measurements and the evaluations are analyzed carefully and the new evaluations are re-recommended.     

The Spectroscopic Systems for the Study of Light Impurity Particle Transport in the HT-7 Tokamak

Three spectroscopic systems have been developed for the study of light impurity particle transport in the HT-7 tokamak. A visible multi-channel spectroscopic system （VIS） is used to obtain the brightness distribution of the line emission from ionized light impurities. The profile of Zeff（r） has been obtained from the visible multi-channel bremsstrahlung measurement （VB）. The system with a rotating hexahedral mirror for space-time resolved spectroscopy measurement from ultraviolet to visible （UV） can provide the brightness distribution of two different emission lines of the light impurities simultaneously. The emissivities by these multi-channel measurements can be obtained by Abel inversion. The measurement was performed in typical OH discharges in the HT-7 tokamak. The carbon particle transport was analyzed. The feasibility of these diagnostic systems for the impurity particle transport study is clearly demonstrated.     

空隙、杂质及组分突变对功能梯度构件动力特性的影响

功能梯度材料具有复杂的细部结构, 其内部构造远比匀质材料复杂, 因此其构件动力分析很难求得其解析解。本文中提出了一种新颖的功能梯度构件动力分析的细观元法, 其目的在于建立材料的宏观性能与其组分材料性能及细观构造之间的定量关系, 以便揭示不同的材料组合及其变异所具有不同的宏观性能的内在机制。利用细观元法对含有空隙、 杂质及组分突变等情况下的功能梯度构件进行动力分析, 求得其三维固有频率及振型的三维分布。从而可知空隙、 杂质及组分突变均对功能梯度材料构件的宏观动力特性有很大的影响。      

非均匀软岩蠕变机理分析

为了对工程围岩的蠕变现象进行解释,探明软岩的蠕变本质,根据岩石压缩过程中变形、弱化本构关系以及变形与承载能力的关系,采用岩石最弱断面并联微元体模型,对非均匀软岩的衰减蠕变和非衰减蠕变机理进行了分析,研究表明,非均匀性岩石内部各点承载能力不同使得变形后岩石内部各点屈服弱化不同步,又由于岩石晶体内部空位或杂质的扩散,二者共同作用导致岩石蠕变．通过对截面积相同,高径比分别为1．5和2．5的页岩岩样进行蠕变试验,验证了岩石的非均匀性是造成岩石蠕变的一个不可忽视的重要因素．     

Effect of Mn Modification on the Corrosion Susceptibility of Mg–Mn Alloys by Magnesium Scrap

The microstructure and anti-corrosion behavior of Mg–Mn alloys by magnesium scrap have been investigated in this study.The results show that the size of the Fe-rich particles in magnesium scrap decreases but the quantity increases with the Mn addition.Although the presence of Mn-containing Fe-rich particles with unique symbiotic structure can eff ectively weaken the micro-galvanic corrosion,the presence of more free Fe(Fe-rich particles) does not necessarily lead to severe corrosion of the alloy.The corrosion susceptibility of Mg–Mn–Fe alloy primarily depends on the solubility of iron in the Mg matrix,while it can be significantly reduced by suitable Mn addition.Besides,the tolerance limit of the Fe impurity can be expressed as Fe_(max) = 0.0083 Mn(relative to the iron solubility).Only when the Fe/Mn ratio is below 0.0083 can the alloy have excellent corrosion resistance,with the corrosion rate changing in the scope of 0.38 ± 0.09 to 0.54 ± 0.15 mg/cm~2 day and i_(corr) from 3 to 9 × 10~(–4) A/cm~2.