ACTIVITIES OF COMPONENTS IN MgO-B_2O_3 MELT

The activity of MgO in MgO-B2O_3 melt was experimentally determined at 1773 and 1823 Kby means of slag-liquid Sn equilibrium.The activity of B_2O_3 was calculated by integratingGibbs-Duhem equation.The standard Gibbs energies of formation of binary compounds2MgOB_2O_3 and 3MgO·B_2O_3 were estimated with the activity data of components inB_2O_3-MgO melt.     

含H_2O气氛下Cu液中Ti的氧化SCIEI

本文研究了1500℃H_2O气氛下液态Cu合金中Ti的氧化。     

Ni3Al合金的滑移特征及形变过程的晶界行为

通过SEM动态拉伸形变试验,研究了具有各种化学成分和不同热处理态Ni_3Al合金的形变滑移特征,并用TEM观察了晶界区域的位错组态。研究结果表明,在含硼Ni_3Al合金的晶界附近存在一个过渡滑移区,该区域中滑移线重新取向或其它滑移系开动,从而产生了局部应变调节并使晶界应力集中松弛。硼降低了开动晶界位错源所需的应力并可能同时增加了位错源本身的数目。硼对Ni_3Al的韧化作用强烈受到基体Al含量、合金元素及热处理等因素的影响。     

稀土元素对Si—Mn—V钢淬火,回火过程中组织结构转变的影响

采用透射电镜,X射线,膨胀仪等方法,对含稀土和不含稀土的4种低、中碳Si—Mn-V钢(20SiMn2V;20SiMn2VRE;40SiMn2V和40SiMn_2VRE)进行了淬火、回火过程中组织结构转变的对比试验,结果表明:稀土元素可以细化低、中碳钢的奥氏体晶粒度;降低M_s点;细化马氏体板条束和板条晶尺寸;并增加中碳钢马氏体中位错亚结构的相对比例。而对低、中碳钢淬火回火组织中残余奥氏体的体积和热稳定性影响甚微。稀土元素明显地抑制了低碳马氏体在低温回火过程中的分解,阻碍板条晶内片状渗碳体的析出,并推迟其长大球化过程。稀土元素也明显地抑制了中碳马氏体中高温回火过程中粒状渗碳体的析出和球化过程。     

双相不锈钢中奥氏体相内裂纹扩展路径的透射电镜原位观察

在透射电镜下原位观察了裂纹在双相不锈钢中的扩展过程。结果表明,裂纹在双相不锈钢中奥氏体晶粒内扩展时常呈较大的Z字形扩展路径。并且,在主裂纹前端奥氏体晶粒内形核的小裂纹与主裂纹有较强的交互作用,小裂纹尖端二次滑移系的选择和扩展路径为小裂纹尖端应力场和主裂纹尖端应力场共同支配。     

非晶合金带的单轴各向异性SCIEI

本文给出了非晶合金带Fe_(54.4)Ni_(36.4)Cu_(0.5)Mn_(0.3)Co_(0.2)Si_(0.2)P_(8.0)室温下的铁磁共振(FMR)谱及谱线形状随θ角的变化(θ角为静磁场H_e与非晶合金带轴方向之间的夹角)。当θ=0°时FMR谱为单峰,当θ=90°时出现明显的复峰,线宽ΔH具有各向异性特性。用FMR理论分析得出非晶合金具有以带轴方向为易轴的单轴各向异性。     

铸钢在凝固区的流变行为SCIEI

用自行设计的流变性能测定仪测量了624钢(32MnNiMoCu)在凝固区内的应力、应变关系。建立了该钢的流变模型、本构方程并确定了流变特性参数。为开展铸钢的应力、应变和热裂纹的计算机数值模拟提供了理论基础及计算数据。     

BEHAVIOUR OF Ti IN AS-CAST MEDIUM MANGANESE AUSTENITIC STEEL

The majority of Ti is found to be preferentially precipitated in the form of TiC from mediummanganese steel melt.The TiC may contribute to the heterogeneous nuclei of fine austenitecrystallization,to the retardation of dislocation movement as well as to pile-up andproliferate the dislocations,thus,the matrix of the as-cast steel will be effectively strength-ened.It was also found that the TiC can be acted as the heterogeneous nuclei of the nodulareutectic carbide formation and caused the dispersion o fan abundance of the carbide in theinterstices between austenite dendrite arms.     

SUPERPLASTICITY OF Al-Zn-Mg-Zr-RE AND Al-Zn-Mg-Ti ALLOYS AND THEIR CAVITATION BEHAVIOUR DURING DEFORMATION

The superplasticity of the Al-Zn-Mg-Zr-RE(alloy A)and Al-Zn-Mg-Ti(alloy B),theirchange of volume fraction of metastable micro-cavities under various reduction of area andstrain rates,as well as the growth of stable cavities in them have been studied by means ofsmall angle X-ray scattering analyses and quantitative metalloraphy respectively.Experimen-tal results show that the volume fraction of metastable micro-cavities of the alloy A is morethan that of the alloy B,but the growth rate of stable cavities in alloy A is less than that in al-loy B.Thus,it is believed that the superplasticity of alloy A is superior to that of alloy B.     

EXTRACTION OF Zn AND Cd FROM CHLORIDE LIQUORS BY TRI-n-BUTYL PHOSPHATE

Studies have been made on the extraction of Zn and Cd by TBP(tri-n-butyl phosphate)from diluent hydrochloric acid solutions of soldium chloride.The experiments show that thespecies extracted from diluent HCI solutions of NaCl appear to be predominantly ZnCl_2·2TBP and CdCl_2·2TBP.For Cd,at lower acidities,anionic complexes of the typeH_2CdCl_3 are also extracted.As the acidity is increased,H_2CdCl_4 appear to be predominantcomplexes in organic phase.For Zn,the acidocomplexes of the type HZnCl_3 appear in organ-ic phase after the acidity of solutions reaching a certain value([HCl]>0.1 mol/L).Furthermore,the ultraviolet absorption spectra of both aqueous and organic phases have beenstudied,and the infrared spectra of the organic phases have been exomined.The extractionmechanism and temperature effect are also discussed.