Processing, Microstructure And Mechanical Properties Of Alalloys Based On Melt Spun Ribbons

In this paper, 7075 Al alloy thin ribbon was prepared by the method of melt spinning.By XRD、OM、SEM、TEM analysis of microstructure of the melt spun ribbon and 120℃,24 h after aging of the melt spun ribbon. The hardness of the two kinds of ribbons was tested by Vivtorinox hardness tester. In microstructure, The microstructure of7075 Aluminum alloy prepared by melt spinning method has the following characteristics:all the alloy elements of 7075 Aluminum alloy were dissolved in the aluminum matrixin,the average grain size of 1.6? m is tested, the dislocation density is 5.7? 1013m-2. The microstructure of aged 7075 Aluminum alloy ribbon has the following characteristics: the average grain size of 1.7?m is tested, the dislocation density is 3.7?1013m-2, In the grain interior containing nanoscale dispersion phase. In mechanical properties, The micro hardness of melt spun 7075 Aluminum alloy ribbon is HV50g=172, compared to the traditional solid solution treatment of coarse grain 7075 Aluminum alloy, the microhardness increased by about 24%. The micro hardness of aged melt spun7075 Aluminum alloy ribbon is HV50g=211, Compared with the traditional coarse grain7075 Al alloy after T6 heat treatment strength of 7075 Aluminum alloy thin sheet was prepared by 120℃/24 h aging treatment increased by about 18%.In this paper, 5083 Al alloy ribbon were also prepared by the method of melt spinning. Nanocrystalline powder was obtained by high energy ball milling using robbins as raw material. then these powders were used for high pressure sintering to obtain5083 Al bulk nanocrystalline materials. The microstructure of powder and bulk material was characterized by XRD, SEM and TEM, The hardness of bulk material was tested by Vivtorinox hardness tester. Preparation of 5083 Al powders containing nanocrystalline by ball milling process, the average grain size is 15.406 nm, the particle size of 3~7?m. And5083 Al bulk nanocrystalline materials were prepared by high pressure sintering at 560℃/5GPa/3h. The high pressure in the process of sintering makes boundary oxide film of ball milling powders is broken, and sintering of powders particles is good, and density is99.7%; At the same time, the nanocrystalline structure is retained, average grain size is80 nm, microhardness is HV200g=241, compared to the traditional coarse grain 5083Al(HV=70~80) increased by more than 300%. This high strength is mainly attributed to grain strengthening and dislocation strengthening and dispersion strengthening effect.Finally, dimple was found in the tensile fracture, It is indicated that the sintering block may have a certain plasticity at the same time with high strength.