Aluminum matrix composites (AMCs) reinforced by 5 wt% B₄C particles were fabricated by direct laser deposition (DLD) technology. The phase composition, microstructure, and microhardness of the B₄C/aluminum matrix composites (B₄C/AMCs) were analyzed by OM, XRD, SEM, TEM, EBSD, microhardness test and molecular dynamics simulation (MD) in detail. The results show that acicular microstructure of AlB₁₂ and Al₄C₃ are formed in the B₄C/AMCs fabricated by DLD. With the addition of B₄C, the crystallographic orientation of AMCs changes from (001) texture to random orientation distribution, and the microhardness increases by about 65%. During the DLD process, boron atoms and carbon atoms are released by B₄C decomposition instead of diffusing through the solid–liquid interface between Al and B₄C, and they react with the liquid Al to produce AlB₁₂ and Al₄C₃ in the molten pool. Moreover, B and C atoms distribute along a strip orientation in the molten pool, which may be retained after the cooling to form the acicular microstructures. This work demonstrates the possibility and good prospects of obtaining AMCs reinforced with B₄C, AlB₁₂ and Al₄C₃ phases by the DLD technique and provides new insights into the microstructural evolution of the composites.

采用直接激光沉积（DLD）技术制备了由 5 wt% B ₄ C 颗粒增强的铝基复合材料（AMC）。_{通过OM、XRD、SEM、TEM、EBSD、显微硬度测试和分子动力学模拟(MD)对B 4} C/铝基复合材料(B ₄ C/AMCs)的物相组成、显微组织和显微硬度进行了详细分析。结果表明，DLD制备的B ₄ C/AMCs中形成了AlB ₁₂和Al ₄ C _{3针状微观结构。随着B 4} C的添加，AMCs的晶体取向由(001)织构转变为随机取向分布，显微硬度增加约65%。在DLD过程中，硼原子和碳原子通过B ₄ C分解释放出来，而不是通过Al和B ₄ C之间的固液界面扩散，它们与液态Al反应生成AlB ₁₂和Al ₄ C ₃熔池。此外，B和C原子在熔池中呈条状分布，冷却后可能保留下来形成针状显微组织。这项工作展示了通过DLD技术获得B ₄ C、AlB ₁₂和Al ₄ C ₃相增强的AMC的可能性和良好前景，并为复合材料的微观结构演变提供了新的见解。