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层状陶瓷与镍扩散连接接头微观组织及性能

Interfacial microstructure and properties of diffusion bonded joints of Ti3AlC2 ceramic and Ni

  • 摘要: 采用扩散连接方式对Ni与Ti3AlC2陶瓷进行连接,为了对Ni与Ti3AlC2的反应层进行详细分析,利用SEM、TEM对接头的微观组织进行研究,了解Ni扩散机制及接头形成机理. 结果表明,在扩散连接过程中,Ni元素向原始Ti3AlC2陶瓷组织的扩散优先沿着晶界及相界面进行,在此处Ni会发生明显的富集,由于Ni与Ti3AlC2陶瓷有较好的化学相容性,因此两者之间能够发生化学反应形成扩散连接接头,随着保温时间的延长,Ni的扩散更加充分,因此形成较为连续的Ni的扩散层. 在扩散连接温度为900 ℃,保温时间为60 min时,Ni与Ti3AlC2陶瓷扩散连接接头的典型界面组织为Ni/Ni3(Al,Ti) + AlNi2Ti + TiC/Ti3AlC2陶瓷,随着扩散连接温度升高,接头抗剪强度表现为先增后减,当扩散连接温度为900 ℃,保温时间60 min,Ni/Ti3AlC2陶瓷接头具有最优的力学性能,抗剪强度可达94.4 MPa.

     

    Abstract: The Ti3AlC2 ceramic and Ni were successfully joined by diffusion bonding technique. The microstructure and element distribution of the joint were analyzed by SEM and TEM. The diffusion mechanism of Ni and the forming mechanism of joint were investigated. The results show that the enrichment of Ni elements adjacent to the Ti3AlC2 ceramic led to a diffusion in the interface, which could promote the formation of joint. The typical interfacial microstructure of the Ni/Ti3AlC2 ceramic joint obtained at 900 ℃ for 60 min is Ni/Ni3(Al,Ti)+AlNi2Ti+TiC/Ti3AlC2 ceramic. It was found that the shear strength of the joint increased with increasing bonding temperature. When the temperature further elevated, the shear strength dramatically decreased. The maximum shear strength is 94.4 MPa at 900 ℃ for 60 min.

     

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