Ti_2Ni/TiNi微叠层复合材料的制备及表征

Synthesis and Characterization of a Ti_2Ni/TiNi Micro-laminated Composite

将Ti箔和Ni箔交替排列,在900℃条件下,通过热压烧结法来制备Ti_2Ni/TiNi微叠层复合材料。研究了保温时间对复合材料的微观组织及相组成的影响。采用扫描电镜(SEM)、电子探针(EPMA)、X射线衍射(XRD)及差示扫描量热分析(DSC)对不同保温时间下制备的复合材料的微观组织、相组成、相结构及相变温度进行分析。结果表明:随着保温时间的增加,Ti和Ni逐渐消耗,在其界面上形成Ti_2Ni、TiNi、Ni_3Ti3种金属间化合物。当Ni消耗完毕,Ti原子向Ni_3Ti层扩散,使之完全转变成TiNi。当Ti完全消耗,仅有交替排列的Ti_2Ni和TiNi两相存在,且在TiNi层上分布着颗粒状和条状的Ti_2Ni相。保温8h后制备的Ti_2Ni/TiNi叠层复合材料的相变温度A_s、A_f、M_s、M_f及相变迟滞温度ΔT分别为75.9,99.2,63.6,45.7和32.5℃。

Using alternatively stacked Ti and Ni foils, a Ti2Ni/TiNi micro-laminated composite was fabricated by hot pressed sintering at 900 ℃. The effect of diffusion time on the microstructure and constitutional phases of the composites was investigated. The scanning electron microscope （SEM）, electron probe microanalysis （EPMA）, X-ray diffraction （XRD） and differential scanning calorimetry （DSC） were employed to analyze the microstructure, constitutional phases, phase structures and phase transition temperatures of the fabricated composites. The results indicate that Ti and Ni foils are gradually consumed with the increase of diffusion time and three intermetallic layers （Ti2Ni, TiNi, Ni3Ti） are produced at the interfaces of Ti/Ni. When Ni foils are completely consumed, Ti atoms diffuse into Ni3Ti layers, transforming the Ni3Ti layers into TiNi. After Ti foils are completely consumed, only alternatively arranged Ti2Ni and TiNi layers exist. Moreover, there are lots of granular and strip-shaped Ti2Ni phases distributing in the TiNi layers. The As, Af, Ms, Mf and transition hysteresis temperature （AT） of the composite fabricated after 8 h diffusion are 75.9, 99.2, 63.6, 45.7 and 32.5 ℃, respectively.