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采用Fe/Al-Si扩散偶的方法,利用SEM-WDS,研究了550℃硅在Fe/Al固态扩散反应中对Fe2Al5生长动力学的影响。实验结果表明,铝中硅含量不超过1.5 wt%时,扩散层中只出现Fe2Al5相,其生长动力学符合抛物线关系,实验测定的铁和铝在Fe2 Al5中的综合扩散系数(D)在含硅量(wt%)分别为0、0.5、1.0和1.5时,分别为3.46×10-15、2.61×10-15、1.28×10-15和0.86×10-15 m2/s。随硅含量增加,其抑制Fe2 Al5相生长速度的效果明显加强。当铝中Si含量为2%和3%时,首先出现Fe2 Al5相。随扩散时间的延长,在Fe2Al5相靠近Al-Si的一侧依次出现了τ1/τ9和τ5相,化合物层生长速度明显加快。由于部分硅以三元化合物的形式存在,导致硅的抑制作用下降。
The effect of silicon on the growth kinetics of Fe2Al5 in the solid solution of Fe / Al diffusion at 550 ℃ was studied by means of Fe / Al-Si diffusion couple and SEM-WDS. The experimental results show that only Fe2Al5 phase appears in the diffusion layer when the content of silicon in aluminum is less than 1.5 wt%. The growth kinetics follows a parabolic curve. The experimental results show that the total diffusion coefficient (D) of iron and aluminum in Fe2Al5 Respectively, were 3.46 × 10-15, 2.61 × 10-15, 1.28 × 10-15, and 0.86 × 10-15 m2 / s when the amounts of silicon (wt%) were 0, 0.5, 1.0 and 1.5, respectively. With the increase of silicon content, the effect of inhibiting the growth rate of Fe2Al5 phase is obviously enhanced. When the aluminum Si content of 2% and 3%, the first Fe2Al5 phase. With the extension of diffusion time, τ1 / τ9 and τ5 phases appeared in turn on the side of Fe2Al5 near Al-Si, and the growth speed of compound layer obviously accelerated. As part of the silicon in the form of ternary compounds, resulting in decreased inhibition of silicon.