Depletion of solutes on particle-Al interfaces in particulates reinforced precipitate-hardening Al composites was harmful to strength. A two-step strategy including bimodal structure design and dislocation assisting low-temperature aging was proposed to enhance the precipitate strengthening in composites. Bimodal structures can redistribute the dislocations from vicinities of particles to coarse grains and increase the density of GNDs under a low strain pre-deformation. Subsequent low-temperature aging at 373 K can eliminate the coarse phases and precipitate-free zones on both grain boundaries and phase interfaces and introduce dense plate precipitates with large aspect ratio in {111}_Al planes, contributing to an ultrahigh strength in bimodal composites without the sacrifice of ductility.

颗粒强化沉淀硬化 Al 复合材料中颗粒-Al 界面上溶质的耗尽对强度有害。提出了包括双峰结构设计和位错辅助低温时效在内的两步策略来增强复合材料中的析出物强化。双峰结构可以将位错从颗粒附近重新分布到粗晶粒，并在低应变预变形下增加 GND 的密度。随后在 373 K 的低温时效可以消除晶界和相界面上的粗相和无沉淀区，并在 {111} _Al平面中引入具有大纵横比的致密板状沉淀物，有助于双峰复合材料的超高强度，而无需延展性的牺牲。