Processing of iron aluminides by pressureless sintering through Fe + Al elemental route
Processing of iron aluminides by pressureless sintering through Fe + Al elemental route
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DOI：
10.1016/s0921-5093(01)01442-3
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发表时间：
2002-02
期刊：
影响因子：
6.4
通讯作者：
S. Gedevanishvili;S. Deevi
中科院分区：
文献类型：
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作者：
S. Gedevanishvili;S. Deevi
在1000-1350℃的温度范围内，通过膨胀实验研究了Fe和Al元素粉末在不同升温速率下的烧结行为。结果表明，FeAl的形成伴随着中间相Fe2Al5的体积变化而膨胀。FeAl的形成机制和最终密度取决于加热速度。慢速加热(≤0.5C分钟−1)的膨胀率为0.0018 mm−1/分钟，而高升温速率(∼1°C分钟−1)时的膨胀率为0.34 mm−1/分钟。较慢的加热速度(≤0.5℃分钟−1)导致Fe2Al5形成时的膨胀较低，随后FeAl的密度较高，最高可达理论密度的94.5%。这是到目前为止(在过去25年中)通过在没有压力的情况下加热元素Fe和Al粉末以在Fe-Al系统中形成FeAl或任何其他金属间化合物而获得的最高密度。用X射线衍射仪、光学显微镜和扫描电子显微镜对Fe+Al混合物在加热过程中形成的相序进行了鉴定。结果与DSC数据一起与样品的膨胀和收缩行为相关联。
The sintering behavior of elemental powders of Fe and Al was investigated at various heating rates by dilatometric experiments in the temperature range of 1000–1350 °C. It was found that the formation of FeAl was accompanied by expansion due to volume change during the formation of the intermediate phase Fe2Al5. The mechanism of FeAl formation and the final density depended on the heating rate. The expansion rate during slow heating (≤0.5 °C min−1) was 0.0018 mm mm−1per min as against ∼0.34 mm mm−1per min at high (≥1°C min−1) heating rates. Slower heating rates (≤0.5°C min−1) lead to lower expansion during Fe2Al5formation and subsequently to a higher density of FeAl up to 94.5% of theoretical. This is the highest density obtained so far (during the last 25 years) by heating elemental Fe and Al powders without pressure assistance to form FeAl or any other intermetallic in the Fe–Al system. The sequence of phases formed during the heating of Fe+Al mixture was identified by X-ray diffraction, optical microscopy and SEM. The results, along with the DSC data were correlated to the expansion and shrinkage behavior of the samples.