Ti2Ni/TiNi微叠层复合材料的制备及表征

Synthesis and Characterization of a Ti2Ni/TiNi Micro-Laminated Composite

摘要:

将Ti箔和Ni箔交替排列,在900_oC条件下，通过热压烧结法来制备Ti₂Ni/TiNi微叠层复合材料。本文研究了保温扩散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Ti₂Ni、TiNi、Ni₃Ti三种金属间化合物。当Ni消耗完毕,Ti原子向Ni₃Ti层扩散,使之完全转变成TiNi。当Ti完全消耗,仅有交替排列的Ti₂Ni和TiNi两相存在,且在TiNi层上分布着颗粒状和条状的Ti₂Ni相。保温8小时后制备的Ti₂Ni/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_oC,99.2_oC,63.6_oC,45.7_oC和32.5_oC。

Abstract:

Using alternatively stacked Ti and Ni foils, a Ti₂Ni/TiNi micro-laminated composite was fabricated by hot pressed sintering at 900 _oC. 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, tranforming 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 A_s, A_f, M_s, M_f and transition hysteresis temperature (ΔT) of the composite fabricated after 8h diffusion are 75.9 _oC,99.2 _oC,63.6 _oC,45.7 _oC and 32.5 _oC, respectively.