Fabrication of light weight materials having ultrafine grain structure through friction stir processing

采用搅拌摩擦法（FRP）加工铸造铝合金ADC12和变形铝合金A5083，以细化晶粒直径。在普通铣床上进行加工。对两种合金经FSP处理后的薄片试样进行了实验研究，并对其组织性能关系进行了分析。结果总结如下：1)不形成三维缺陷的FSP最佳条件；决心作为一个革命的速度985 rpm和转换速度的88毫米/分钟alloys2) FSP带来微观结构组成的罚款和equi-axed谷物平均直径几μm3)的颗粒直径倾向于减少数量的减少FSP alloys4)大型平板状硅阶段的起始物料ADC12铝合金改为多个统一和球状粒子μm diameter5) FSPed标本显示机械6)经FSP处理的ADC12合金的铸造合金试样在高温下表现出大于500%的超塑性伸长率，这可能是由于FSP带来的细晶粒组织

Friction stir processing (FRP) has been exploited to cast aluminum alloy ADC12 and wrought aluminum alloy A5083 in order to refine the grain diameter. The processing was performed with an ordinary milling machine. A sheet specimen of both alloys subjected to FSP without any special pretreatment and its microstructure-property relationship was experimentally examined. The results are summarized as follows1) The optimum condition for FSP under which no 3-D defects are formed, was determined as a revolution speed of 985rpm and transition speed of 88mm/min for both alloys2) FSP brought about a microstructure consisting of fine and equi-axed grains with an average diameter of several μm3) The grain diameter tended to decrease with decrease in the number of FSP for both alloys4) Large plate-like phase of silicon in the starting material of ADC12 alloy changed to a number of uniform and spheroidal particles of several μm in diameter5) FSPed specimens showed the mechanical properties at room temperature considerably close to those of parent material6) Cast alloy specimen of alloy ADC12 subjected to FSP showed superplastic elongation larger than 500% at high temperature, probably due to the fine grain structure brought about by FSP