【摘要】 采用镶嵌式技术制备了Al/Fe扩散偶,在铝熔点以上铁熔点以下进行扩散热处理,对Al/Fe液-固界面扩散反应层的生长动力学进行了分析,并建立了生长动力学方程。结果表明,Fe2Al5是热处理保温过程中唯一生成的新生相。在Fe2Al5连续单相层形成之前,其生长受Al原子和Fe原子的化学反应控制;一旦连续的Fe2Al5单相层形成,其生长则主要依赖于Al原子沿其晶界的扩散控制,且伴随着其晶粒尺寸的长大。在800℃以下热处理,可忽略晶粒长大对原子扩散的影响,其生长动力学方程为:y=2020.96exp(-78490/RT)t0.25。但当热处理温度超过铁熔点的0.7倍后,则不能忽略晶粒长大的影响,应适当减小生长动力学方程中的生长指数值。更多还原

【Abstract】 The Al/Fe diffusion couples were prepared by using the inset technology and diffusion heat treated at the temperature above the melting point of aluminum and below the melting point of iron.The growth kinetics of the diffusion reaction layer(DRL)of Al/Fe liquid-solid interface was analyzed and the growth kinetics equation was established.The results show that Fe2Al5 is the only new phase formed during the heat treatment temperature holding process.The growth of the Fe2Al5 is controlled by the chemical reaction of the Al atoms and Fe atoms before the Fe2Al5 continuous single-phase layer is formed.Once the continuous Fe2Al5single-phase layer is formed,its growth is primarily dependent on the diffusion of Al atoms along Fe2Al5 grain boundaries,accompanied with Fe2Al5 grain size increasing.When heat treatment below 800℃,the effect of the grain growth on the diffusion of atoms can be ignored,and the growth kinetics equation is y=2020.96exp(-78490/RT)t0.25.But,when the heat treatment temperature is 0.7times exceeding the melting point of iron,the effect of grain growth can not be ignored,and the value of the growth index in the growth kinetics equation should be reduced appropriately.更多还原