EFFECT OF STRUCTURAL RELAXATION ON THE DEFORMATION BEHAVIOR OF A Zr64.13Cu15.75Ni10.12Al10 BULK METALLIC GLASS UNDER NANOINDENTATION

Structural relaxation by isothermal annealing below the glass transition temperature is conducted on a Zr64.13Cu15.75Ni10.12Al10 bulk metallic glass. The effect of structural relaxation on thermal and mechanical properties was investigated by differential scanning calorimetry and instrumented nanoindentation. The recovery of the enthalpy in the DSC curves indicates that thermally unstable defects were annihilated through structural relaxation. During nanoindentation, the structural relaxation did not have a significant influence on the serrated plastic flow behavior. However, Structural relaxation shows an obvious effect in increasing both the hardness and elastic modulus, which is attributed to the annihilation of thermally unstable defects that resulted from the relaxation

贵金属纳米材料生物还原制备技术的研究进展

综述了国内外利用生物还原技术制备贵金属纳米材料及贵金属催化剂的研究进展,并展望了该研究领域的发展方向

Analysis of the Festo CLR Cylinder Performance

本文对Clr气缸工作性能的实验研究,目的是为了满足数控机床气动随行夹具中气缸的旋转夹紧要求。利用PlC控制器、气阀、气缸、传感器等元器件搭建实验平台。对主要实验步骤进行详细分析,通过实验论证fESTO Clr直线摆动夹紧气缸完全满足气动随行夹具工作要求。In this paper,we introduced an experiment to study the performance of pneumatic cylinder.In order to meet the requirements of the line/rotation clamping cylinder in CNC machine tools pneumatic clamp accompanied system.Using PLC controller,valves,cylinders,sensors and other components to build an experimental platform,the main experimental steps have been analyzed in details.Through the different kinds of experimental data demonstrating the Festo CLR line/rotation clamping cylinder is fit for the requirement of practical work

GaNxAs1-x(x＜0.01)中合金态的光学特性

应用多种光谱手段研究了分子束外延生长在半绝缘的(001,GaAs衬底上的低氮含量的GaNAs中三元合金态的光学特性.变温PL谱揭示了合金态的本征特性以及其与氮的杂质态的根本区别,而脉冲激发的光荧光谱则进一步显示了合金态的本征光学特性.最后还研究了GaNAs的吸收光谱特征

Characterization Of Shear Bands In Two Bulk Metallic Glasses With Different Inherent Plasticity

Shear banding characterization of Zr64.13Cu15.75Ni10.12Al10 and Zr65Cu15Ni10Al10 bulk metallic glasses (BMGs) with significant difference in inherent plasticity and quite similar chemical composition was studied by depth sensitive macroindentaion tests with conical indenter. Well-developed shear band pattern can be found for both BMGs after indentation. Distinct difference in the shear band spacing, scale of plastic deformation region and the shear band branching in the two BMGs account for the different plasticity

X射线辐照对发根农杆菌介导芸芥遗传转化的影响

探讨了X射线辐照对芸芥发状根诱导的影响,为研究辐射对转基因技术的协同作用提供一定的实验依据。以芸芥无菌苗的子叶为材料,通过5—20Gy的X射线辐照和不等浸染时间的联合处理,研究苗龄、预培养时间、辐照剂量及其浸染时间等因素对芸芥发状根诱导的影响作用,并通过聚合链酶式反应(PCR)对所得发状根进行了分子水平的鉴定。15GyX射线辐射能提高芸芥发状根的诱导频率,且有量效关系,其中先浸染后辐照比先辐照后浸染效果更显著;PCR结果也表明,发根农杆菌R1000的rolB基因已成功地被转入并整合到该发状根的基因组中。X射线辐照对芸芥发状根的诱导具有一定的促进作用,且最佳推荐诱导剂量为15Gy或稍多

Serrated Plastic Flow During Nanoindentation in Nd-Based Bulk Metallic Glasses

The microstructure of Nd_{60}Al_{10}Ni_{10}Cu_{20-x}Fex (x = 0, 5, 7, 10, 15, 20) alloys can change from homogeneous phase to a composite structure consisting of amorphous phase plus clusters or nanocrystals by adjusting the Fe content. The effect of microstructure on the plastic deformation behavior in this alloy system is studied by using nanoindentation. The alloys with homogeneous amorphous structure exhibit pronounced flow serrations during the loading process of nanoindentation. The addition of Fe changes the plastic deformation behavior remarkablely. No flow serration is observed in the alloys with high Fe content for the indentation depth of 500 nm. The mechanism for the change of plastic serrated flow behavior is discussed

CHARACTERIZATION OF SHEAR BANDS IN TWO BULK METALLIC GLASSES WITH DIFFERENT INHERENT PLASTICITY

Shear banding characterization of Zr64.13Cu15.75Ni10.12Al10 and Zr65Cu15Ni10Al10 bulk metallic glasses (BMGs) with significant difference in inherent plasticity and quite similar chemical composition was studied by depth sensitive macroindentaion tests with conical indenter. Well-developed shear band pattern can be found for both BMGs after indentation. Distinct difference in the shear band spacing, scale of plastic deformation region and the shear band branching in the two BMGs account for the different plasticity

Serrated Plastic Flow During Nanoindentation in Nd-Based Bulk Metallic Glasses

The microstructure of Nd60Al10Ni10Cu20-xFex (x = 0, 5, 7, 10, 15, 20) alloys can change from homogeneous phase to a composite structure consisting of amorphous phase plus clusters or nanocrystals by adjusting the Fe content. The effect of microstructure on the plastic deformation behavior in this alloy system is studied by using nanoindentation. The alloys with homogeneous amorphous structure exhibit pronounced flow serrations during the loading process of nanoindentation. The addition of Fe changes the plastic deformation behavior remarkablely. No flow serration is observed in the alloys with high Fe content for the indentation depth of 500 nm. The mechanism for the change of plastic serrated flow behavior is discussed. (C) 2004 Elsevier Ltd. All rights reserved

Serrated Flow and Shear Band Evolution in A Zr-Based Bulk Metallic Glass After Plastic Deformation and Annealing

The effect of pre-deformation and annealing on serrated plastic flow and shear band features of a Zr-based bulk metallic glass was investigated through nanoindentation and macroindentation tests. The results showed that the serrated plastic flow during the loading process of nanoindentation was significantly suppressed in pre-deformed sample and re-appeared after subsequent annealing. The effect of pre-existed shear bands on the development of final shear bands was characterized by macroindentation without bonded interfaces. Pre-deformation does not lead to the multiply of shear band during the consequent plastic deformation, but decrease the shear band number significantly. The change in plastic flow behavior of the alloy by pre-deformation is thought to be the preferential propagation of existed shear bands, and its effect can be eliminated by annealing below glass transition temperature. (C) 2010 Elsevier B.V. All rights reserved