非平衡凝固下Nd_8Fe_(86)B_6合金的显微组织及凝固行为

Non-equilibrium Solidification Process and Microstructure of Nd_8Fe_(86)B_6 Alloy

研究非平衡凝固条件下Nd8Fe86B6合金显微组织和凝固行为的变化规律。结果表明,Nd8Fe86B6合金随着冷却速度的增大,组织发生明显变化。当冷却速率低于1.3×103K/s,组成相为Nd2Fe14B、-αFe和富B相;冷却速率介于1.3×103~3.95×105K/s之间组成相为Nd2Fe14B和-αFe相;当冷却速率介于3.95×105~4.51×105K/s时,相组成为Nd2Fe14B相和非晶相;冷却速率大于5.39×105K/s时组织为完全的非晶相。随着冷却速率的增大,各个相的尺寸由微米级别减小到纳米级别。

The non-equilibrium solidification process and the microstructure of Nd8Fe86B6 alloy were studied.The results show that the microstructures of the alloy changed with the increase in cooling rate.The phases were composed of Nd2Fe14B,α-Fe and boron rich phase at the cooling rate below 1.3×103 k/s.However,the phases consisted of Nd2Fe14B and α-Fe in the cooling rate range of 1.3×103~3.95×105 K/s.There were Nd2Fe14B with grains in nanometer size and most amorphous in the range of 3.95×105~4.51×105 K/s.As the cooling rate beyond 5.39×105 K/s,there were entirely in the amorphous state,and the sizes of each phase decreased from micron to nanometer.