Effect of Si content on interfacial reaction and properties between solid steel and liquid aluminum

Si含量对固态钢/液态铝界面反应与界面力学性能的影响

The effect of Si content on the microstructures and growth kinetics of intermetallic compounds(IMCs)formed during the initial interfacial reaction(<10 s)between solid steel and liquid aluminum was investigated by a thermophysical simulation method.The influence of Si addition on interfacial mechanical properties was revealed by a high-frequency induction brazing.The results showed that IMCs layers mainly consisted ofη-Fe_(2)Al_(5)andθ-Fe_(4)Al_(13).The addition of Si reduced the thickness of the IMCs layer.The growth of theηphase was governed by the diffusion process when adding 2 wt.%Si to the aluminum melt.When 5 wt.%or 8 wt.%Si was added to aluminum,the growth was governed by both the diffusion process and interfacial reaction,and ternary phaseτ1/τ9-(Al,Si)_(5)Fe_(3)was formed in theηphase.The apparent activation energies of theηphase decreased gradually with increasing Si content.The joint with pure aluminum metal had the highest tensile strength and impact energy.

采用热物理模拟方法研究Si含量对固态钢与液态铝界面反应初始阶段(反应时间<10 s)内金属间化合物的显微组织和生长动力学的影响。同时,通过高频感应加热的方式研究Si添加对钢/铝界面力学性能的影响。结果表明,在界面反应初期,金属间化合物层主要包括η-Fe_(2)Al_(5)和θ-Fe_(4)Al_(13)两相。铝液中添加Si后金属间化合物层的厚度减小。当Al液中含2%Si(质量分数)时,η相的生长仅由扩散过程控制;当铝液中Si含量增至5%或8%时,η相的生长由扩散过程与界面反应共同控制,同时,τ1/τ9-(Al,Si)_(5)Fe_(3)三元相也在η相中形成。随着铝液中Si含量的增加,η相的激活能逐渐减小。界面力学性能结果显示,纯铝与钢形成的接头具有最高的抗拉强度和冲击功。