The effect of Cr content and cooling rate on the microstructure of Al-Mn alloy was studied using well resistance furnace melting, and the alloy was analyzed using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The experimental results showed that adding Cr could significantly improve the morphology of the primary phase in the Al-2.5Mn alloy. Without Cr, the primary phase in the alloy was thick, needle-like, and strip-like structure. After adding 0.2wt%-0.5wt% Cr, the primary phase in the upper part of the alloy was gradually fined and reached the best effect at 0.35wt% Cr. When the content of Cr was 0.5wt%, the microstructure of the primary phase in the upper part began to coarsen. The bottom of the alloy was a large bulk phase, but still much finer than that without adding Cr. XRD and SEM analysis showed that the precipitation phase at the bottom was mainly Al₈₅Mn₇Cr₈, while the fine microstructure at the top was Al₆Mn and Al₃Mn. The results of the cooling rate experiments showed that the primary phase of Al-2.5Mn-0.35Cr was further refined, and the eu-tectic microstructure was partly achieved, under air-cooling condition. And when the cooling method was iron die-cooling, the microstructure of the Al-2.5Mn-0.35Cr alloy was changed into a eutectic microstructure.

利用电阻炉熔炼研究了Cr含量和冷却速率对Al-Mn合金组织的影响，并通过扫描电子显微镜（SEM）和X射线衍射（XRD）分析了合金的含量。实验结果表明，添加Cr可以显着改善Al-2.5Mn合金中初生相的形貌。没有Cr，合金中的主要相是厚的，针状和条状结构。加入0.2wt％-0.5wt％Cr后，合金上部的初生相逐渐细化，并在0.35wt％Cr处达到最佳效果。Cr含量为0.5wt％时，上部的主相的组织开始粗大化。合金的底部是大块状相，但比不添加Cr的相要细得多。₈₅ Mn ₇ Cr ₈，而顶部的细微组织为Al ₆ Mn和Al ₃ Mn。冷却速率实验的结果表明，在空冷条件下，Al-2.5Mn-0.35Cr的初生相得到了进一步细化，部分达到了共晶组织。并且，当冷却方法为铁模冷却时，Al-2.5Mn-0.35Cr合金的组织变为共晶组织。