A comparative study of the role of solute,potent particles and ultrasonic treatment during solidification of pure Mg,Mg-Zn and Mg-Zr alloys  

作　　者：Nagasivamuni Balasubramani Gui Wang Mark A.Easton David H.St John Matthew S.Dargusch 

机构地区：[1]Centre for Advanced Materials Processing and Manufacturing(AMPAM),School of Mechanical and Mining Engineering,The University of Queensland,Brisbane 4072,Australia [2]School of Engineering,RMIT University,Carlton,3053 VIC,Australia

出　　处：《Journal of Magnesium and Alloys》2021年第3期829-839,共11页镁合金学报（英文）

基　　金：the funding support provided by Australian Research Council Research Hub for Advanced Manufacturing of Medical Devices IH150100024;the ARC Discovery grant DP140100702 and ARC linkage project LP150100950。

摘　　要：Ultrasonic treatment(UST)applied during the solidification of pure Mg,eutectic(Mg-Zn)and peritectic(Mg-Zr)alloys was investigated in order to explore the grain refinement mechanisms.Temperature dependent grain refinement is observed in pure Mg where decreasing the superheat temperature(at which UST is applied from above the melting temperature,TM)from 100℃to 40℃produces significant refinement with a uniform grain structure.The presence of solute reduces the temperature dependence of the UST refinement and excellent grain refinement is obtained regardless of the superheat temperature(100℃or 40℃)and even with the use of preheated sonotrode in the Mg-6 wt.%Zn alloy.A further improvement in grain refinement is achieved when the alloy contains potent particles that introduce additional nucleation of grains in Mg-0.5 and 1.0 wt.%Zr alloys(producing an average grain size of≤100μm).At 40℃superheat,UST of Mg-Zn alloys produces excellent refinement(average grain size<200μm)with non-dendritic grains,which is normally achieved only with the addition of grain refining master alloy in the as-cast condition.The enhanced refinement observed in the eutectic alloy is explained through the undercooling imposed by a relatively cold sonotrode combined with high frequency vibrations and acoustic streaming.The advantages of using a cold sonotrode,a low superheat and solute are demonstrated for achieving significant refinement during solidification of Mg alloys under UST without or with a lower addition of grain refining master alloys.

关 键 词：Grain refinement Mg-Zn alloy Mg-Zr alloy Ultrasonic treatment Interdependence Model SOLIDIFICATION 

分 类 号：TG146.22[一般工业技术—材料科学与工程]