Development of New Type Cu Base Alloys Obtained by Controling Ordering and Phase Separation

已知Cu-Al-Mn合金β相中存在A2/B2/D03/L21有序-无序转变、有序相的磁转变和相分离等多种转变。本研究的目的是利用这些相变来开发一些新型的铜基合金。本文研究了高强度铜合金、形状记忆合金和巨磁阻薄膜。研究结果如下：(1)高强度Cu合金：Cu-13% al -15% mn -5% ni合金经300℃时效处理，拉伸强度达到1000MPa以上。通过透射电镜观察，时效试样的显微组织为一种具有极细尺度的贝氏体组织。由于除Cu- be合金外，尚无其他铜基合金具有如此高的强度，因此本文所述合金有可能成为一种新型的高强度铜基合金。(2)形状记忆合金：考察了合金元素对可加工性、Ms温度和SM性能的影响。结果表明，Si、Au和Co的析出降低了合金的塑性，提高了合金的Ms温度，而SM性能受晶粒尺寸和织构的影响较大。(3)研究了不同成分Cu-Al-Mn合金的巨磁阻薄膜gmr性能。结果表明，体积分数为Cu2MnAl:Cu3Al=3:7的Cu-25%Al-10%Mn合金GMR比在4%以上时最高。在此基础上，正在与一些公司开展实际应用的联合项目。

It is known that there are many kinds of transformations, such as A2/B2/D03/L21 order-disorder transitions, magnetic transition and phase separation in their ordered phases, in the β phase of the Cu-Al-Mn alloys. The purpose of this study is to develop some new types of Cu base alloys using these transformations. Actually high strength Cu alloys, shape memory (SM) alloys and giant magnetoresistance (GMR) thin films were examined in the present study. All the results obtained in this study are listed as follows :(1) High Strength Cu Alloys :In the Cu-13%Al-15%Mn-5%Ni alloys, very high level of tensile strength over 1000MPa were achieved due to aging at 300℃. According to TEM observation, it is seen that the microstructure of the as-aged specimens has a kind of bainate structure with very fine scale. Since such the high level of strength in the Cu base alloys has not been reported except the Cu-Be alloys, the present alloys have a potential for a new kind of high strength Cu base alloys.(2) Shape Memory AlloysEffects of alloying elements on the fabricability, Ms temperature and SM properties were examined. It was clarified that the precipitates decrease ductility, Si, Au and Co increase the Ms temperature and the SM properties are strongly influenced by grain size and texture.(3) Giant Magnetoresistance Thin FilmsGMR properties of Cu-Al-Mn alloys with wide range of compositions were examined. It was clarified that the Cu-25%Al-10%Mn alloy which has the volume fraction of Cu2MnAl:Cu3Al=3:7 shows the highest GMR ratio over 4%.Based on the above results, joint projects for practical applications with some companies are running.