Yeon-Wook Kim
材料科学技术（英）
Mg-Al-Zn-MM (misch metal) alloy powders were manufactured by inert gas atomization and the characteristics of alloy powders were investigated. In spite of the low fluidity and easy oxidation of the magnesium melt, the spherical powder was made successfully with the improved three piece nozzle systems of gas atomization unit. It was found that most of the solidified powders with particles size of less than 50 μm in diameter were single crystal and the solidification structure of rapidly solidified powders showed a typical dendritic morphology because of supercooling prior to nucleation. The spacing of secondary denrite arms was deceasing as the size of powders was decreasing. The rapidly solidified powders were consolidated by vacuum hot extrusion and the effects of misch metal addition to AZ91 on mechanical properties of extruded bars were also examined. During extrusion of the rapidly solidified powders, their dendritic structure was broken into fragments and remained as grains of about 3 μm in size. The Mg-Al-Ce intermetallic compounds formed in the interdendritic regions of powders were finely broken, too. The tensile strength and ductility obtained in as-extruded Mg-9 wt pct Al-1 wt pct Zn-3 wt pct MM alloy were σT.S.=383 MPa and ε=10.6%, respectively. All of these improvements on mechanical properties were resulted from the refined microstructure and second-phase dispersions.
关键词:
Mg alloy
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null
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null
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null
Wei Qiu
材料科学技术（英）
In this work, the influence of element RE on the microstructures and mechanical properties of the hot extuded Mg-3Al-1Zn-xRE alloys (with element RE content of 0.05, 0.1 and 0.2 wt pct) has been investigated and compared. It was found that RE can bring about precipitations phase that is identified as Al11RE3 by X-ray diffraction and transmission electron microscopy (TEM). The grain sizes would not be refined after adding RE element. Al11RE3 phase would increase strength and decrease the ductility. The addition of RE element affects dynamic recrystallized process and even reorientation of recrystallized grains. The results showed that the mechanical properties of AZ31+RE alloy are affected by combination of Al atoms, Mn atoms, Al11RE3 phase and grains orientation. It is important to consider the ratio of RE/Al when designing new Mg-Al-RE alloys.
关键词:
Mg alloy
Byoungho Kim
,
Jongjin Jeon
,
Yeongdo Park
,
Yongho Park
,
Ikmin Park
材料科学技术（英）
The ageing behavior of Mg-xAl-Zn alloys with a variation of Al contents (x=3, 5, 7, 9 and 11 wt pct) were investigated. Solid solution treatment and artificial ageing were carried out at 693 and 493 K, respectively. After the solid solution treatment, β-Mg17Al12 was resolved to the α-Mg matrix in the specimens which contained Al up to 9 wt pct and partially resolved in the specimen of 11 wt pct Al. During ageing, the β-Mg17Al12 phase was precipitated at the grain boundary in the form of discontinuous precipitation and grown into the matrix. The volume fraction of β-phase was increased with the Al contents. Tensile strength increased with the volume fraction of precipitated β-phase, which was believed to strengthen the matrix.
关键词:
Ageing
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null
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null
刘庆
金属学报
doi:DOI: 10.3724/SP.J.1037.2010.00446
简述了具有密排六方(hcp)结构镁合金材料各种可能的滑移和孪生系统及其临界切变应力; 以镁合金塑性变形机理为主线, 分别对单晶和多晶镁合金材料塑性变形行为及微观机理的影响规律, 轧制、挤压及不同严重塑性变形模式下镁合金织构的形成机理, 形变镁合金材料退火过程中回复与再结晶及镁合金材料在热变形过程中的动态再结晶机理, 以及沉淀硬化镁合金塑性变形机理、特别是沉淀相与位错滑移及孪生的交互作用机理等进行了总结与评述. 同时, 对高成形性镁合金及提高镁合金塑性成形能力的塑性变形机理进行了讨论.
关键词:
镁合金
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plastic deformation
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mechanical twinning
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dislocation slip
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texture
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anisotropy
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recrystallization
高继峰
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刘德绪
,
龚金海
,
王勇
腐蚀与防护
采用电化学阻抗谱(EIS)、动电位极化曲线、失重法和扫描电镜研究了磷酸一氢钠对AZ91镁合金在0.05％NaCl溶液中的缓蚀行为,及其与部分有机物的协同作用.结果表明,因为磷酸一氢根离子与镁离子反应产生了镁盐沉淀物,磷酸一氢钠对镁合金有一定的缓蚀作用;有机磺酸盐、羧酸盐或氨酸盐单独使用时,这些缓蚀剂的阴离子可以部分吸附在镁合金表面上,从而起到一定程度的保护作用;磷酸一氢钠与磺酸盐复配使用时缓蚀效率最高.
关键词:
缓蚀剂
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镁合金
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磷酸一氢钠
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电化学方法
张静
,
袁付庆
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豆雨辰
,
张旭峰
,
汤爱涛
材料热处理学报
研究了添加稀土Er（0～4.0%）对半连续铸造ZK21合金铸态和均匀化态组织的影响。结果表明,稀土Er的添加可有效细化铸态组织,加入2.0%的Er使合金的平均晶粒尺寸由94μm细化至62μm,减小了34%。Er在均匀化态合金中部分固溶于基体中,部分与Mg、Zn元素形成热稳定Mg-Zn-Er三元化合物相;当稀土含量高于0.5%时,合金中不存在二元Mg-Zn相。随着稀土含量的增加,Er在基体中的固溶度增大,化合物的体积百分数增多,与此同时,Zn在基体中的固溶度减少。合金的硬度在Er含量为2.0%时达到最大,这是基体中Zn、Er元素固溶强化和析出相强化的综合作用结果。
关键词:
镁合金
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稀土
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均匀化
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显微组织
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硬度
