Abstract
Flywheel shells with a complex structure and large wall-thickness difference,as key components in heavy trucks,serve to connect the engine and transmission.Formability and mechanical performance control of such components should be taken into consideration.In this work,an Al-Si-Fe-Mn-Mg-Cu alloy was used to manufacture the flywheel shell via squeeze casting.The role of local loading on microstruc-ture and mechanical property at thick-walled positions was investigated.Furthermore,the effect of the squeeze casting specific pressure and heat treatment on the microstructure and mechanical property of the Al-Si-Fe-Mn-Mg-Cu alloy flywheel shells was also analyzed.The results showed that at the thick-walled positions,local loading not only helped eliminate the solidification defects,but also refined the microstructure including α-Al grains and secondary dendrite arm spacing.With increasing the squeeze casting specific pressure from 24 MPa to 32 MPa,microstructure refinement and mechanical property en-hancement of squeeze casting flywheel shells were obtained.After T6 heat treatment,the yield strength and ultimate tensile strength of flywheel shells were further increased to 261.8 and 318.4 MPa,respec-tively,owing to the formation of spherical eutectic Si phases and nano-sized β'',Q and S precipitates.
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