【摘要】 利用亚快速定向凝固设备制备Nd-Fe-B合金,并研究了其定向凝固组织。设计合金成分为:亚包晶成分(Nd10.8Fe83.8B5.4)、包晶成分(Nd11.76Fe82.36B5.88)和过包晶成分(Nd13.5Fe79.75B6.75)。对抽拉速率在5~500μm/s范围内合金的定向凝固及微观组织的研究表明:三种成分Nd-Fe-B合金的最终凝固组织均由α-Fe枝晶相、包晶Nd2Fe14B相和富Nd相组成;随着抽拉速率的提高,α-Fe相的一次枝晶间距呈减小的趋势;三种成分凝固组织中的α-Fe相的体积分数随着抽拉速率的提高都表现出了先减后增的趋势,而Nd2Fe14B相的体积分数都表现出了先增后减的趋势。更多还原

【Abstract】 The solidification microstructure of Nd _x Fe 100-1.5x B 0.5x （x =10.8%,11.76%,13.5%） alloys are researched at the withdraw velocity ranging from 5μm/s to 500μm/s under directional solidification. The results indicate that the final microstructure of three compositions alloys is all primary α-Fe phase, Nd₂Fe 14 B phase and Nd-rich phase. With increase of withdraw velocity, primary dendrite arm spacing of primary α-Fe phase decreases, the volume fraction of primary α-Fe phase decreases and then increases,Nd₂Fe 14 B phase increases and then decreases.更多还原