超细晶粒W-Ni-Fe合金烧结收缩动力学特征

Shrinkage Kinetics during Sintering W-Ni-Fe Heavy Alloy with Ultrafine Grain

利用高温膨胀仪在氢气气氛下测定和研究了粉末平均晶粒≤１５０ｎｍ的Ｗ－（Ｎｉ－Ｆｅ） １０％合金在烧结过程中的膨胀─收缩动力学曲线特征、起始收缩温度、剧烈收缩温度、收缩速 率与Ｗ粉的平均粒径、烧结温度、升温速度以及压坯密度的关系．结果发现超细粉末压坯开始 及剧烈收缩温度分别为９７０℃和１２４０℃，最大收缩速率为ｇμｍ／℃．压坯密度愈高，合金收缩率 愈低；压坯密度一定时，烧结温度愈高，合金收缩率愈大．

The characteristics of swell-shrinkage kinetic curve during sintering the compact of W-Ni- Fe 10% with primary mean grain size less than 200 nm in hydrogen atmosphere was researched by high tem- perature dilatometer. And the effects of the average size of tungsten particle and green density on shrinkage commence temperature, sharp shrinkage temperature and shrinkage rate were also studied. It shows that shrink age commence temperature and sharp shrinkage temperature of the compact with ultrafine grain are 970℃ and 1240 ℃ respectively. The maximum shrinkage rate is 9 μm/℃. The shrinkage ratio decreases with the increase of green density and increases with the increase of sintering temperature.