TA2/不锈钢/Q235复合板的界面结构和失效行为

Interface structure and failure behavior of TA2/stainless steel/Q235 composite plate

采用热轧复合法制备了TA2/不锈钢/Q235复合板,并对其开展了不同温度的轧后退火处理。利用扫描电镜、能谱以及X射线衍射等分析了退火温度对复合板界面附近微观组织、金属间化合物等特征的影响。通过显微硬度计和平面内压缩试验研究了退火温度对复合板变形以及力学性能的影响。结果表明:从不锈钢侧到钛侧,界面依次由σ相(富Cr的Fe基固溶体)、χ相(富Cr的TiFe^(2)相)、TiCr_(2)+TiFe_(2)、TiFe等化合物组成。随着退火温度的升高,σ相和TiFe的层厚相较于χ相和TiCr_(2)+TiFe_(2)增加更明显。显微硬度测试表明,随着退火温度的升高,Q235层硬度逐渐降低,而Ti层硬度则是先降低后升高,硬度升高主要与元素扩散有关。平面内压缩过程中,会发生TA2与不锈钢之间的层间开裂,且随着退火温度的升高,层间开裂越早,这主要与越厚的金属间化合物易萌生裂纹有关。

TA2/stainless steel/Q235 composite plate was prepared by hot rolling bonding method,and post-rolling annealing treatments at different temperatures of the composite plate were carried out.The effects of annealing temperature on microstructure and intermetallic compounds near the interface of the composite plate were analyzed by means of scanning electron microscopy,energy dispersive spectroscopy analysis and X-ray diffraction.The effect of annealing temperature on the deformation behavior and mechanical properties of the composite plate was studied by microhardness tester and in-plane compression test.The results show that from the stainless steel side to the titanium side,the interface is mainly composed ofσ-phase(Cr-rich Fe-based solid solution),χ-phase(Cr-rich TiFe_(2)phase),TiCr_(2)+TiFe_(2),and TiFe.With the increase of annealing temperature,the thickness increment of theσ-phase and TiFe layer is larger than that of theχphase and TiCr_(2)+TiFe_(2)layer.Microhardness test shows that with the increase of annealing temperature,the hardness of the Q235 layer decreases gradually,while the hardness of the Ti layer first decreases and then increases,and the increase of hardness is mainly related to element diffusion.Interlaminar cracking between TA2 and stainless steel occurs during in-plane compression.The higher the annealing temperature is,the earlier the interlaminar cracking occurs,mainly because the thicker intermetallic compound is easy to initiate cracks.