亚微晶2024铝合金的制备及组织性能研究

将快速凝固２０２４铝合金粉末进行机械球磨，并分别将球磨后的粉末与原始的快速凝固粉末经真空热压制坯及热静液挤压成形。采用透射电镜观察了挤压态及时效状态的微晶２０２４铝合金的组织结构并进行了性能测试。研究结果表明，经过机械球磨后，２０２４铝合金的强度明显提高，并随着球磨时间的增加而增高，延伸率保持在原有水平上，微晶２０２４铝合金的强化机制可能是细晶强化及沉淀强化。此外，由于晶粒细小而导致晶内位错极少，造成明显的拉伸屈服现象，同时材料的加工硬化率降低。

PREPARATION AND MECHANICAL PROPERTY OF 2024 ALUMINIUM ALLOY WITH SUBMICRON GRAINS

Rapidly solidified 2024 aluminum alloy powders were mechanically milled in high energy mill machine,then consolidated to bulk form by hot hydrostatic extrusion and aged in different time.The mechanical properties of the extruded and the aged materials were measured,and the microstructures were observed by transmission electron microscopy.The results showed that mechanical milling can improve the strength of rapidly solidified 2024 without loss of ductility,and the aging increases the strength of mechanically alloyed 2024 further,which are owing to refined grains and dispersion precipitation.In addition,mechanical milling decrease the work hardening rate because of refined grains and less dislocation.