摘要
采用大挤压比热挤压为预变形方式的SIMA法制备了5083铝合金半固态坯料,研究了挤压比、等温热处理温度与保温时间等工艺参数对半固态坯料微观组织演变的影响,并通过SEM和能谱线扫描分析了等温热处理温度对5083铝合金主要元素成分偏析的影响规律。结果表明,SIMA法制备5083铝合金半固态坯料的微观组织受工艺参数影响较大,当挤压比为17.36,等温温度为605～610℃,保温时间为15～20min时,可以获得较理想的5083半固态坯料。另外,5083铝合金中Mn元素的分布基本不受等温热处理温度影响,但Al、Mg元素的分布受温度影响较大,等温温度越高,偏析越严重;在晶界处偏析的低熔点相主要由Mg元素构成。
Semi-solid 5083 aluminum alloy billets were prepared by SIMA with hot extrusion at high extrusion ratio for pre-deformation. Effects of some processing parameters,such as extrusion ratio,isothermal temperature and holding time,on microstructure evolution of the semi-solid alloy billets were investigated,and influences of isothermal temperature on the segregation of dominant elements in the alloy billets were observed by SEM (scanning electron microscope) and EDS. The results indicate that microstructure evolution of the semi-solid alloy billets prepared by SIMA is closely related to the processing parameters. Desirable semi-solid 5083 alloy billets can be obtained with the extrusion ratio of 17.3 at 605℃ for 15~20 min. Distribution of the Mn element in the alloy is independent of the isothermal temperature ,however,distribution of Al,Mg element are dependent on the temperature,where segregation is more and more serious with increasing in isothermal temperature. Low point phase segregated from the grain boundary is mainly composed of Mg element.
出处
《特种铸造及有色合金》
CAS
CSCD
北大核心
2010年第9期823-826,共4页
Special Casting & Nonferrous Alloys
基金
国家自然科学基金资助项目(50774035)
