Han ZHANG and Qingrong FENG (Dept. of Physics
,
Peking University
,
Beijing 100871
,
China)Y.Zhao(School of Materials Science and Engineering
,
University of New South Wales
,
Sydney 2052
,
NSW
,
Australia)F.Ritter and W.Assmus (Physikalisches Institut
,
J.W.Goet
材料科学技术（英文）
Bi2Sr2CaCu2Ox superconductor was studied by differential scanning calorimetry (DSC) and thermogravimetry (TG) in different atmospheres. It is discovered that there is a thermal anomaly in the DSC curve, associated with a weight loss in the TG curve before the melting of the sample. Careful thermal analysis and high temperature X-ray diffraction reveal that the thermal anomaly and the weight loss show an instability of the crystalline Iattice. By annealing the sample in oxygen and argon, respectively and then by TC measurement and thermal analysis, the coincidence of transition temperature with the instability is found. The coincidence is further confirmed by Y-doped 2212 phase.
关键词:
殷福星
金属学报
名义组分为Mn-20Cu-5Ni-2Fe(原子分数，％)的M2052合金，具有很高的强度和阻尼性能．对该合金在不同条件下的阻尼性能采用多种方法进行了表征．该合金的高阻尼态出现在一个临界温度以下，该温度可以通过改变组分和热处理来调整．合金的室温阻尼性能强烈地依赖于频率、应变振幅以及静载荷的大小．
关键词:
阻尼合金
,
null
,
null
,
null
卢凤双
,
芮永岭
,
田宇鹏
,
张建福
,
冯强
,
赵栋梁
金属功能材料
金属阻尼材料是一种用来减振和降噪的结构功能一体化材料,利用其制造相关振动源构件,可以有效地解决机械制造及相关工程领域中的振动和噪声问题.介绍了近年发展起来的新型MnCu可变形M2052 (Mn-20Cu-5Ni-2Fe)合金的阻尼机理、研究开发过程以及应用前景,并提出该合金的一些研究方向.
关键词:
M2052
,
阻尼合金
,
内耗
王铸博
,
卢凤双
,
吴滨
,
徐然
,
张建福
,
赵栋梁
,
罗丰华
功能材料
doi:10.3969/j.issn.1001-9731.2016.09.041
采用单质Mn、Cu、Ni、Fe粉末,通过反应烧结过程可制备 M2052合金.主要研究了烧结温度对密度、孔隙率和力学性能的影响,同时对烧结样品的相组成进行了分析.M2052合金在950℃烧结时基本为γ-MnCu固溶体,合金的密度为6．23 g/cm3,致密度为87．2％,抗弯强度达到了487 MPa,并具有良好的阻尼性能,不同频率下的阻尼性能表现稳定,损耗因子tanδ达到0．11~0．12.
关键词:
锰铜合金
,
阻尼能力
,
粉末冶金
谢晋武
,
刘文博
,
李宁
,
颜家振
,
钟珍玉
,
刘颖
,
赵修臣
功能材料
doi:10.3969/j.issn.1001-9731.2015.13.019
通过砂型铸造法控制 MnCu 合金的凝固过程，获得具有显著成分偏析的枝晶组织，能够进一步促进时效过程中调幅分解的发生，是提高其阻尼性能的又一有效途径。采用 JN-1倒扭摆、OLYMPUS 显微镜、SEM、DMA、XRD等手段，系统研究了枝晶偏析对M2052合金阻尼性能的影响。结果表明，铸造 M2052合金在铸态下，已含有少量孪晶马氏体，具有一定的阻尼性能；且经过435℃×4 h 时效处理后，该合金的阻尼性能明显提高(δ＝0．26)，甚至超过锻造 M2052合金(δ＝0．20)。这主要是由于铸造成分偏析的富 Mn区可促进纳米级高富 Mn 区的形成，明显提高Ms 点(85℃)，使冷却过程中生成更多数量的孪晶马氏体，从而获得优异的阻尼性能。
关键词:
砂型铸造
,
枝晶偏析
,
铸造 M2052 合金
,
孪晶马氏体
,
富Mn区
,
Ms 点
Acta Materialia
Dislocation densities and dislocation structure arrangements in cold compressed polycrystalline commercial M2052 (Mn-20Cu-5Ni-2Fe) high damping alloy with various strains were determined in scanning mode by X-ray peak profile analysis and electron backscatter diffraction (EBSD). The results indicate that the Mn-Cu-Ni-Fe alloy has an evolution behavior quite similar to the dislocation structure in copper. The dislocation arrangement parameter shows a local minimum in the transition range between stages III and IV that can be related to the transformation of the dislocation arrangement in the cell walls from a polarized dipole wall (PDW) into a polarized tile wall (PTW) structure. This evolution is further confirmed by the results of local misorientation determined by EBSD. In addition, during deformation, the multiplication of dislocation densities in the MnCu alloy is significantly slower than that in copper, and the transition of the dislocation structure is strongly retarded in the MnCu alloy compared with copper. These results can be explained by the mechanism of elastic anisotropy on the dislocation dynamics, as the elastic anisotropy in the MnCu alloy is larger than that in copper, which can strongly retard the multiplication of the dislocation population and the transformation of the dislocation structure. These results are important for research into the plastic working behavior of Mn-Cu-Ni-Fe high damping alloy. (C) 2007 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
关键词:
Mn-Cu alloy;X-ray diffraction;electron backscatter diffraction;dislocation;stacking fault energy;stacking-fault energy;line-profile analysis;shape-memory alloys;x-ray-diffraction;electron-microscopy;fcc metals;crystals;contrast;behavior;polycrystals
