Hot Tearing Susceptibility Of Mg-10Zn-(x)Al Alloys Using Instrumented CRC Mold And Validity Of Theoretical Hts From Pandat's Pan Mg Database

There is a greater need to pursue the research on development of light alloy multi-materials system to integrate them in BIW?Body in White?applications during these transition stage between gasoline–hybrid–New energy vehicle in the automobile industry.Die casting is one of the common manufacturing process in the production of automotive components.Although research on Mechanical properties and Die cast-ability of Mg-Zn-?x?Al to eliminate the problematic Mg₁₇A₁₂ phase in Mg-Al alloy is widely reported,investigation about the effect of Al content in Hot Tearing Susceptibility?HTS?of high Zinc containing Mg-10Zn alloy is rarely reported with inadequate explanation about the characteristics of hot tearing curves.High Zinc containing alloys are known to completely suppress the formation of Mg₁₇A₁₂ phase and thus HTS investigation on High Zinc containing Mg-Zn alloy is a time bound goal.Hot tearing is a common defect faced during the solidification process of an alloy in castings and welding,particularly a major concern in the castings of Zinc containing Mg alloys.In this work,Hot tearing of Mg-10Zn alloy is studied and the effect of varying Al content?wt%?on the HTS of Mg-10Zn alloy is investigated.More careful analysis on the volumetric contraction force curve patterns obtained during solidification process of an alloy at different initial mold temperatures?280?,320?,350??through the use of CRC?Constrained Rod Casting?equipped with Load cell,thermo-couple and DMS?Data Management System?.The experimental results indicate that Al addition reduces HTS of Mg-10Zn alloy.The plot of experimental HTS results as function of Al content yields a linear downward slope line.Drop in Load force values?DI?during solidification indicate the hot tear initiation,DI values of ZA107>ZA105>ZA102>Mg-10Zn alloy indicating tear initiation in all of the investigated alloys but HTS results of ZA107<ZA105<ZA102<Mg-10Zn alloy.Eutectic healing was observed in the Al containing alloys at Higher initial mold temperatures.The results also suggest that increasing Al content enabled hot tearing resistant property of Mg-10Zn alloy by facilitating liquid feed for the strain developed during mid–stage of solidification?0.65F_s⁰.74F_s?.Experimental HTS results of Mg-10Zn-?x?Al were compared with Theoretical predicted crack susceptibility index values.Comparison of Experimental and predicted HTS of binary Mg-Zn,Mg-Y and Mg-Al alloys were made.Further,influence of other alloying elements namely Ag,Cu and Li on the HTS of ZA105 alloy studied using pandat's solidification curve and Kou's criterion index.