In this study, an Al–based composite reinforced with nanometric γ–Al₂O₃ and submicron AlB₂ particles was fabricated via chemical reactions between Al and boron oxide, followed by hot extrusion. The volume fraction of in–situ formed γ–Al₂O₃ and AlB₂ is 11.2 vol% and 6.3 vol%, respectively. The average size of γ–Al₂O₃ and AlB₂ is around 50 nm and 500 nm, respectively, and the α–Al grain is 1.26 µm in the longitudinal section. The γ–Al₂O₃ particles either distribute inside of α–Al grains or exhibit particle chains or networks locating along grain boundaries, while AlB₂ particles are uniformly distributed among the matrix grains. The Young’s modulus is averaged at 91 GPa, and the ultimate tensile strength and elongation of the composite at room temperature are averaged to be 426 MPa and 8.1 %, respectively. The yield strength at 350 °C is as high as 217 MPa. It is regarded that the relatively fine α–Al grains along with the γ–Al₂O₃ particles inside of α–Al grains and AlB₂ particles are mainly responsible for room temperature strengthening, while the γ–Al₂O₃ particle chains or networks along grain boundaries play the key role in grain boundary strengthening at 350 °C. This work may provide new insights for designing and fabricating Al–based composite for elevated–temperature application.

在这项研究中，通过铝和氧化硼之间的化学反应，然后进行热挤压，制备了一种用纳米γ - Al ₂ O ₃和亚微米 AlB ₂颗粒增强的铝基复合材料。原位形成的γ - Al ₂ O ₃和AlB ₂的体积分数分别为11.2 vol%和6.3 vol%。γ - Al ₂ O ₃和AlB ₂的平均尺寸分​​别约为50 nm和500 nm，纵向截面上的α-Al晶粒为1.26 µm。γ _-Al ₂ O ₃颗粒要么分布在α-Al晶粒内部，要么呈现出沿晶界定位的颗粒链或网络，而AlB ₂颗粒均匀分布在基体晶粒之间。杨氏模量平均为 91 GPa，室温下复合材料的极限拉伸强度和伸长率平均分别为 426 MPa 和 8.1 %。350℃屈服强度高达217MPa。认为相对细小的α-Al晶粒以及α-Al晶粒内部的γ - Al ₂ O ₃粒子和AlB ₂粒子对室温强化起主要作用，而γ - Al_{沿晶界的2} O ₃粒子链或网络在 350 °C 的晶界强化中起关键作用。这项工作可能为设计和制造用于高温应用的铝基复合材料提供新的见解。