Internal friction change of Al, Mg-alloys in terms of casting method

摘要

Mg alloys (AZ91) were manufactured by sand-casting and gravity-casting method, and Al alloys (ADC12) by die-casting for the application of automotive engine parts. Internalfriction of each alloy was measured using the sonic resonancesystem by free decay method as a function of frequency andtemperature. To compare with the measured internal friction valueof Mg(AZ91) , Al(ADC12) alloys produced in this study, weobtained die cast Mg alloys (AZ91) manufactured by Toyota,Dainhatsu and GM, and Al alloys (ADC10) by Toyota. For Mgalloys, specimens produced by die casting showed higher value ininternal friction than ones by sand-casting and gravity-casting,mainly due to the difference in grain size. Mg alloys produced bydie-casting showed higher internal friction than Al alloys producedby the same method. internal friction values measured at 393K forMg alloys (AZ91) increased with increasing frequency.