The Influence Of Refinment On The Microstructure And Properties Of The Casting Aluminum Alloy

The influence of several kinds of grain refiners,differences of the modification temperature,remelting number and differences of the join method on the microstructure and properties of the ZL101 alloy were studied. Researched the different grain refiners on the properties of the different thickness ZL101 wheel influence.The results show that the microstructure of casting Al-Si alloy consisted of a+(α+β) phase and a small amount of Mg2Si without refinement, a needleβphase which distribute in the bound of the grain of the a phase, and the microstructure is coarse。Sr refining processing can not only refining a phase, also refining eutectic silicon phase, The coarse Silicon phase plate. The satisfactory refinement in microstructure of the ZL101 can be observed with addition of 0.06% Sr, which results in the increase of mechanical properties. With 50%SrCl2+50%NaF mixed modification, theαphase surface smooth degree increased without refinement,βphase transforming into granular structure which distribute in the bound of the grain of the a phase. Test materials were added to the Wtl.4% SrCl2+NaF treatment, with the good thinning effect and highest mechanical property. The microstructure of the ZL101 get the best effect with the grain refiners join in the 0.14% of Ti, the microstructure of ZL101 consisted of refining alpha phase and short flake eutectic silicon which distribute in the bound of the grain of the a phase. The microstructure of the ZL101 get the best refining effect with the grain refiners join in the 0.06% of B, consisted of dendrite a phase, sheets and short flake eutectic silicon which distribute in the bound of the grain. When Al-5Ti-B addition is 0.06%, the microstructure of test materials can be refined. With the different grain refiners of the treatment effect, Sr metamorphism and SrCl2+NaF composite metamorphic to refining eutectic silicon effect is good, and the dendrite a phase can be refined, the dendrite a phase can be improved by Ti.B and Ti-B grain refiners.SrCl2 refining of the best join method as the agent of bell jar or mixing method. KBF4 best to join method as the bell jar method, at the same time the material strength of the experiment is highest, the microstructure of ZL101 became tiny and symmetrical and the mechanical properties was batter with the modification temperature in 700～730℃.The microstructure of ZL101 was more sensitive to remelting with SrCl2 and Al-10Sr grain refiners, the mechanical properties reduced with increase the remelting number. The refining recession is not obvious by Sr. the microstructure of ZL101 alloy also keep more fine after refining for 6 h. Sr+Na refined effect can keep 3 h, and the refined effect fade with increasing of holding time.T6 heat treatment after Casting Al-Si alloy refining with the different grain refiners, the microstructure of ZL101 was consisted of the a phase and the reinforced Mg2Si and granularβphase which distribute in the bound of the grain of the a phase,T6 heat treatment can increasing the mechanical properties of materials with varying degrees. The microstructure of ZL101 alloy of wall thickness sensitivity is larger without refinement, the smaller of the wall thickness the thinner of the microstructure, refining the more obvious effect, the effect of thickness is smaller sensitivity by Sr grain refiner, and different wall thickness experiment materials are good refined effect.