Meiyan ZHAN
金属学报(英文版)
In the present investigation a wrought magnesium alloy AZ31 was successfully processed by the accumulative roll-bonding (ARB) at gradient temperature up to six cycles with the lowest temperature of 250℃. This is performed through different thermomechanical processing routes (different ARB cycles at different temperatures of 350-200℃). The microstructures and mechanical properties were investigated. The results indicate that significant grain refinement is observed after the first two cycles at the highest ARB temperature as a result of dynamic recrystallization, which is necessary for the subsequently ARB cycles at relatively lower temperature with the aim to restrict grain growth. No significant finer grain size was observed through the fifth and sixth cycles while the microstructure homogeneity is further improved. The grain structure can be effectively refined at lower ARB processing temperature and higher cycles. The resulting material exhibited high strength and relatively high ductility at ambient temperature when ARB deformed above 250℃. The mechanical properties of the ARB deformed materials are strongly dependent on several main factors: the amount and the homogeneity of strain achieved, grain size and microstructure homogeneity, textures developed during ARB and interface bonding quality.
关键词:
Mg-Al-Zn magnesium alloy
马跃群
,
梁松茂
,
陈荣石
,
韩恩厚
金属学报
本文采用冷却曲线热分析法和连续扭矩测试技术对AZ6x（x=0~6）合金系列的泥区特性进行了表征及分析。结果表明：随着锌含量的增加，AZ6x合金初晶形核第一特征温度Tn1、初晶形核第二特征温度Tn2以及枝晶闭合温度Tch均逐步降低，（Tn1-Tn2）温差逐渐增加，（Tn2-Tch）温差变化不大；AZ6x合金的枝晶闭合固相分数fs-ch约为0.27~0.35，AM60和AZ66合金的fs-ch稍高，锌含量2~5wt%合金的fs-ch稍低，AZ62合金的fs-ch最低；随着锌含量的增加，AZ6x合金的枝晶硬化温度Tpk逐渐降低，Tpk处的固相分数逐渐降低，Tpk处的泥区强度值先升后降，锌含量2~5wt%合金的泥区强度增长速度相对缓慢；冷却曲线热分析法和连续扭矩测试技术的结果具有可比性。
关键词:
Mg-Al-Zn镁合金
,
mushy zone
,
shearing strength
