强磁场对半无限Al/Cu固液扩散偶凝固组织的影响

采用半无限Al/Cu扩散偶法,对磁场下Al-Cu合金凝固组织进行研究.结果表明:由于沿扩散方向Cu原子分数逐渐减小,凝固时,沿凝固方向依次生成α-Al胞/枝状晶等组织、Al-Al2Cu共晶组织和Al2Cu过共晶组织;在不同磁感应强度下(0～12 T),各组织发生了明显变化,胞状晶消失,枝晶粗化并发生偏转;共晶组织层间距与磁感应强度呈非线性关系,组织被扭曲;过共晶组织界面形貌变平整;Cu原子扩散距离缩短.利用XRD对α-Al枝晶区进行衍射分析,发现磁场下α-Al(100)晶面峰值强度变弱,(111)晶面变强.理论分析认为,强磁场对熔体流动的抑制作用和磁场下晶体的磁各向异性是导致上述现象的主要原因...

Effect of High Magnetic Field on Solidification Structure of Half-Infinite Liquid Al/Solid Cu Diffusion Couple

The solidification of Al-Cu alloy was investigated by the liquid Al/solid Cu diffusion couples under the high magnetic field.The results showed that the α-Al cellular/dendrite crystal,Al-Al2Cu eutectic lamellar and Al2Cu hypereutectic are formed separately along the solidification direction.When a high magnetic field(up to 12 T) is applied to the liquid Al/solid Cu couples,the cellular crystals disappear,the primary dendrite arms coarsen and deflect from the solidification direction,the eutectic is distorted and its spacing depends nonlinearly on the magnetic field intensity,the interface of hypereutectic becomes regular,and the diffusion distance of Cu atoms decreases.XRD results showed that the peak strength of the α-Al(100) crystal plane becomes weak,but that of the(111) crystal plane is stronger.Those phenomena may be attributed to the magnetic field suppressing melt flow and the magnetic anisotropy.