低压脉冲电场参数对半固态AZ91D镁合金初生相的影响  

Effect of Parameters of Low-Voltage Electric Current Pulse on Primary Phase of Semi-Solid AZ91D Alloy

作　　者：周全[1] 

机构地区：[1]南昌航空大学材料科学与工程学院,江西南昌330063

出　　处：《铸造》2009年第9期899-902,共4页Foundry

基　　金：江西省教育厅资助项目(GJJ08208);江西省自然科学基金资助项目(2008GQC0035)

摘　　要：研究了低压脉冲电场作用下半固态AZ91D镁合金的制备,考察了脉冲电压、放电电容、处理时间及放电周期对半固态合金组织的影响。研究结果表明:利用低压脉冲放电可以制备出初生相为球状或近球状晶体的半固态AZ91D镁合金。半固态合金的初生相颗粒大小和圆度系数随着放电电容、脉冲电压和处理时间的增加而逐渐减小;但当放电电压达到400V时,其值略有增加。随着放电周期的增加,半固态合金的初生相颗粒大小和圆度系数逐渐增加。当放电周期为6s,放电电容为18800μF,脉冲电压为300V,处理时间为20min时,半固态合金的初生相颗粒尺寸最为细小,形态最为圆整,适合于半固态成形。Preparation of semi-solid alloy of AZ91D by low-voltage electric current pulse discharge was studied, and the effect of discharging cycle, voltage, capacitance and time On microstructure of semi-solid alloy of AZ91D was investigated. The experimental results show that semi-solid alloy of AZ91D with nondendritic structure could be obtained by low-voltage electric current pulse discharge treatment. On the one hand,, the particle size and sphericity of primary α-Mg grains in the alloy decrease with the increase of discharging voltage, treating time and capacitance. But when discharging voltage increases further to 400 V, the grain size and sphericity rebounds slightly. On the other hand, both the particle size and sphericity increase as discharging cycle increases. When prepared at such conditions as the discharging cycle 6 s, the discharging capacitance 18 800 pF, the discharging voltage 300 V, and the discharging time 20 min, the semi-solid alloy with the finest microstructure can be obtained, which is basically suitable for thixoforming.

关 键 词：低压脉冲电场 半固态 镁合金 

分 类 号：TG146.22[一般工业技术—材料科学与工程]