摘要
通过新SIMA法制备Mg-Al-Zn合金半固态坯的触变挤压和触变模锻试验以及借助金相显微镜、拉伸试验机等分析手段对Mg-Al-Zn合金半固态坯的制备及触变成形进行了研究。研究结果表明,新SIMA法中的等径道角挤压能使Mg-Al-Zn合金获得良好的应变诱导效果,即铸坯微观组织被大大细化,平均晶粒尺寸达到20μm,材料力学性能大幅度提高;该坯料在560℃保温20min制备的半固态坯料的固相晶粒细小,球化程度高,组织均匀,平均晶粒尺寸为25μm。通过触变挤压和触变模锻试验证明,新SIMA法制备的Mg-Al-Zn合金半固态坯料所触变成形的零件的力学性能很高。其中触变挤压的卫星角框零件的屈服强度、抗拉强度和伸长率分别为213.1MPa、312.6MPa和15.2%。触变模锻的托弹板零件的屈服强度、抗拉强度和伸长率分别为218.6MPa、320.9MPa和14.8%。
Thixo-squeezing and thixo-forging of Mg-Al-Zn alloy semi-solid billets prepared by new SIMA method were carried out.Preparation and thixo-forming characteristics of Mg-Al-Zn alloy semi-solid billets were understood by OM(optical microscope)and tensile testing machine.The results reveal that microstructure of the Mg-Al-Zn alloy can be greatly refined as a result of desirable strain induction effects by equal angular extrusion(ECAE)in new SIMA method,in which average grain size of 20μm can be obtained and which are responsible for the obvious improvement of mechanical properties of the alloy.The spheroidized fine grain with average size of 25μm in the microstructure with uniform distribution of the semi-solid billets can be prepared by ECAE with holding at 560 ℃ for 20 min.Thixo-squeezing and thixo-forging experiment verify that the mechanical properties of the thixo-forming Mg-Al-Zn parts can be improved greatly,and the yield strength,tensile strength and elongation of thixo-squeezed satellite angle frame are 213.1 MPa,312.6 MPa and 15.2%,respectively,while those of thixo-forged magazine plate are 218.6 MPa,320.9 MPa and 14.8%,respectively.
出处
《特种铸造及有色合金》
CAS
CSCD
北大核心
2008年第6期432-434,共3页
Special Casting & Nonferrous Alloys
基金
国家自然科学基金资助项目(50605015)
