MICROSTRUCTURE AND MECHANICAL PROPERTIES OF Mg-Li ALLOY WITH Ca ADDITION

Mg-9wt%Li-2wt%Zn alloy was prepared and studied in this article. The addition of Ca to the alloy from 0.1wt% to 1wt% can refine the α-Mg and the best effect of refinement occurs when Ca content is 0.4wt%-0.5wt%. The billets can be rolled to thin sheets at room temperature, from which it is obvious that the addition of Ca improves alloys ormalin. while it decreases with the excess addition of Ca. The results also show that the ultimate tensile strength （UTS） and yield strength （YS） of the alloy with lwt% Ca may rise by 28% and 25%, respectively, however, the elongation decreases. It is clarified that the adsorption of proper Ca on the grain boundaries refines α-Mg and improves the tensile properties, but the presence of excess Ca and stable Ca2Mg6Zn3phase worsens the elongation.     

MICROSTRUCTURE AND MECHANICAL PROPERTIES OF A Ni_3Al-Fe BASED ALLOY

The microstructure,tensile properties at 20—950℃ and creep rupture properties at 700-900℃ in a Ni_3Al-Fe based alloy after high temperature deformation have been studied.Theresults show the microstructure of the alloy is composed of γ′-and β-phases.The grain sizeand yield strength of the alloy is stable when the temperature≤600℃,and it is ductile athigh temperature.The creep of the alloy at 700—900℃ is controlled by the climbing of dislo-cations,and the activation energy for creep is 439 KJ/mol with a stress exponent of 4.     

MICROSTRUCTURE AND MECHANICAL PROPERTIES OF A EXTRUDED RAPIDLY SOLIDIFIED AIFeVSi ALLOY

ＭＩＣＲＯＳＴＲＵＣＴＵＲＥＡＮＤＭＥＣＨＡＮＩＣＡＬＰＲＯＰＥＲＴＩＥＳＯＦＡＥＸＴＲＵＤＥＤＲＡＰＩＤＬＹＳＯＬＩＤＩＦＩＥＤＡＩＦｅＶＳｉＡＬＬＯＹ￥Ｚｅｎｇ，Ｙｕｘｉａｏ；Ｌｉ，Ｓｏｎｇｒｕｉ；Ｌｉ，Ｗｅｎｘｉａｎ；Ｗａｎｇ，Ｒｉｃｈｕ；Ｈｕ...     

EFFECTS OF SMALL Ag ADDITIONS ON MECHANICAL PROPERTIES AND MICROSTRUCTURE OF ALLOY 2195

ＥＦＦＥＣＴＳＯＦＳＭＡＬＬＡｇＡＤＤＩＴＩＯＮＳＯＮＭＥＣＨＡＮＩＣＡＬＰＲＯＰＥＲＴＩＥＳＡＮＤＭＩＣＲＯＳＴＲＵＣＴＵＲＥＯＦＡＬＬＯＹ２１９５￥ＨｕａｎｇＢｉｐｉｎｇ；ＺｈｅｎｇＺｉｑｉａｏ；ＹｉｎＤｅｎｆｅｎｇ；ＭｏＺｈｉｍｉｎｇ（Ｄｅｐａ...     

MICROSTRUCTURE AND MECHANICAL PROPERTIES OF Fe_3Al BASED ALLOYS

ＭＩＣＲＯＳＴＲＵＣＴＵＲＥＡＮＤＭＥＣＨＡＮＩＣＡＬＰＲＯＰＥＲＴＩＥＳＯＦＦｅ_３ＡｌＢＡＳＥＤＡＬＬＯＹＳＤ．Ｇ．ＭＯＲＲＩＳ（ＩｎｓｔｉｔｕｔｅｏｆＳｔｒｕｃｔｕｒａｌＭｅｔａｌｌｕｒｇｙ，ＡｖｅｎｕｅｄｅＢｅｌｌｅｖａｕｘ５１，Ｕｎｉｖｅｒ?..     

EFFECT OF MELT SUPERHEATING ON MICROSTRUCTURE AND MECHANICAL PROPERTIES OF A357 ALLOY

ＥＦＦＥＣＴＯＦＭＥＬＴＳＵＰＥＲＨＥＡＴＩＮＧＯＮＭＩＣＲＯＳＴＲＵＣＴＵＲＥＡＮＤＭＥＣＨＡＮＩＣＡＬＰＲＯＰＥＲＴＩＥＳＯＦＡ３５７ＡＬＬＯＹ①ＬｉＰｅｉｙｏｎｇ１，２，ＪｉａＪｕｎ，ＧｕｏＪｉｎｇｊｉｅ，ＬｉＰｅｉｊｉｅ，ＳｈａｏＧａｏｌｉａ...     

MICROSTRUCTURE AND MECHANICAL PROPERTIES OF AN Al-Li-Cu-Mg-Zr ALLOY CONTAINING MINOR LANTHANUM ADDITIONS

The effect of the addition of minor amounts of La on the microstructure and mechanicalproperties of an Al-Li-Cu-Mg-Zr alloy was studied.The results showed that in Al-Li alloyssome impurities,such as Fe,Si and Na segregated on the grain boundaries,and the addition ofminor amounts of La decreased the segregation of these impurities.In addition,La could giverise to grain refinement,and retard the growth of precipitates.The tensile properties andtoughness of the Al-Li alloy containing minor amounts of La were improved compared with theLa-free Al-Li alloy.     

MECHANICAL PROPERTIES IMPROVEMENT OF TiAl BY MICROSTRUCTURE REFINING

ＭＥＣＨＡＮＩＣＡＬＰＲＯＰＥＲＴＩＥＳＩＭＰＲＯＶＥＭＥＮＴＯＦＴｉＡｌＢＹＭＩＣＲＯＳＴＲＵＣＴＵＲＥＲＥＦＩＮＩＮＧＨｕａｎｇＢａｉｙｕｎ；ＨｅＹｕｅｈｕｉ；ＫｏｎｇＧａｏｎｉｎｇ；ＱｕＸｕａｎｈｕｉ（ＰｏｗｄｅｒＭｅｔａｌｌｕｒｇｙＲｅｓｅａ...     

EFFECT OF SOLUTION TREATMENT IN AN ELECTRIC FIELD ON MECHANICAL PROPERTIES AND MICROSTRUCTURE OF 2091 Al—Li ALLOY

Solution treatment of 20% Al-Li alloy in an electric field has been studied The results show that it increases the solubility of elements and accelerates the nucleation ofT_1-phaseand promotes the formation of the precipitation free zones(PFZ), and increases the strength and decreases the plasticity ofthe allov.     

MICROSTRUCTURE AND MECHANICAL PROPERTIES OF TiAl Nd ALLOYS

ＭＩＣＲＯＳＴＲＵＣＴＵＲＥＡＮＤＭＥＣＨＡＮＩＣＡＬＰＲＯＰＥＲＴＩＥＳＯＦＴｉＡｌ＋ＮｄＡＬＬＯＹＳ￥ＬｅｉＣｈａｎｇｍｉｎｇ；ＨｅＹｕｅｈｕｉ；ＣｈｅｎＳｈｉｑｉ；ＱｕＸｕａｎｈｕｉ；ＨｕａｎｇＢａｉｙｕｎ（Ｒｅｓｅａｒｃｈｉｎｓｔｉｔｕｔｅｏ...     

Zn—Al合金热型连铸定向凝固的晶体生长机理

对热型连铸条件下Zn-Al系列合金引锭时的晶体形核和随后的本的竞争生长过程进行了探讨,组织观察表明,单向热流条件下引锭端部生核的晶粒当其枝晶择优生长方向与热流方向一致时才能生长,其它取向的晶粒逐渐被淘汰,合金的凝固特性对选晶过程有极大的影响,ZA5和ZA8合金由于凝固范围窄,晶体直接由引锭端部的晶粒通过竞争生长获得柱状晶组织,ZA12,ZA22和ZA27含Al量高,凝固范围宽,其平行柱状晶组织是从引锭端部的等轴晶区发展而来的。     

电磁离心铸造NiAl共晶合金的显微组织和力学性能

利用电磁离心铸造(EMCC)工艺制备NiAl/Cr(Mo)共晶合金,研究了合金的显微组织和压缩性能.结果表明, 合金显微组织细小,由激冷区、共晶区和亚共晶区组成.激冷区以初生β-NiAl相为主,共晶区由β-NiAl和α-Cr(Mo)相构成,亚共晶区由初生β-NiAl和β-NiAl/α-Cr(Mo)共晶组成. EMCC NiAl共晶合金1000℃压缩行为遵从幂指数规律: ε=Aσn.合金的室温断裂方式以基体NiAl的解理断裂和NiAl/Cr(Mo)的相界面剥离为主.     

MICROSTRUCTURE AND MECHANICAL PROPERTIES OF 8090 Al-Li ALLOY

The change of mechanical properties of the 8090 Al-Li alloy influenced by aging is attributedto the change of δ′-phase particle size and the precipitation of S′-phase.The δ′-phase mayeasily precipitate and rapidly grow,but the S′-phase can only precipitate with a longer stageof incubation.The precipitation of S′-phase would be promoted by cold working prior to ag-ing.The co-precipitation of δ′- and S′-phase could improve the strength and plastieity of thealloy,for which aging at 190℃.for 20—30 h seems to be optimal.In addition,the precipitatefree zone( PFZ)can form at high angle grain boundary and its width is over 200 nm in peakaging condition.But at sub-grain boundary,the formation of PFZ is difficult.     

CONTINUOUS CASTING TECHNOLOGY OF SINGLE CRYSTAL COPPER ROD

ＣＯＮＴＩＮＵＯＵＳＣＡＳＴＩＮＧＴＥＣＨＮＯＬＯＧＹＯＦＳＩＮＧＬＥＣＲＹＳＴＡＬＣＯＰＰＥＲＲＯＤ①ＸｕＺｈｅｎｇｍｉｎｇ,ＬｉＪｉａｎｇｕｏａｎｄＦｕＨｅｎｇｚｈｉＳｔａｔｅＫｅｙＬａｂｏｒａｔｏｒｙｏｆＳｏｌｉｄｉｆｉｃａｔｉｏｎＰｒｏｃｅｓ...     

8090Al-Li合金的微观结构与力学性能SCIEI

本文系统地研究了8090Al-Li合金的微观结构与力学性能的关系。结果表明,合金性能的变化主要归因干δ′颗粒尺寸的变化和S′相的析出。δ′相容易析出并迅速长大,而S′相析出的孕育期较长,时效前冷变形可促进S′相析出。δ′相和S′相共同析出可改善合金强度和塑性,其最佳时效条件为190℃,20—30h。另外,在有平衡相析出的高角晶界容易形成无沉淀区,在峰值时效条件,其宽度可达200nm以上,但在亚晶界难以形成。     

高拉速板坯连铸结晶器液态渣消耗机理分析

基于弯月面渣道压力计算,分析2.0 m/min高拉速下板坯连铸结晶器振动周期内初凝坯壳变形行为,提出新的液态渣消耗机制,并定义了渣耗时间和渣耗强度的概念,阐明了结晶器非正弦振动参数对液态渣渣耗量影响规律.研究表明:渣道宽度变化引起渣道压力改变导致液态渣周期性持续消耗,振动正滑脱末期至负滑脱末期渣道负压抽吸液态渣进入渣道;降低振频延长了液态渣渣耗时间,但使渣耗强度削弱;提高振幅可加大渣耗强度,对渣耗时间影响很小;非正弦振动因子对渣耗强度影响较小,渣耗时间随非正弦振动因子减小而增大.     

高拉速板坯连铸结晶器液体摩擦机理分析

基于液态渣动量和质量守恒原理,建立结晶器非正弦振动模式下弯月面区液体摩擦力计算模型,通过分析2.0 m·min-1拉速时液体摩擦力极值问题,提出新的液体摩擦机制.研究表明:液体摩擦力受渣道形状、熔渣池深度和结晶器与铸坯间相对运动状态等影响,并随振动波形变化;理想状态下最大液体摩擦力发生在振动速度与拉速相等时刻附近;表面裂纹生成于临近负滑脱段的正滑脱时段内,并在负滑脱段得到愈合.     

Ni3Al—Fe基合金组织与力学性能的研究

本文研究了合金化的Ni_3Al-Fe基合金高温变形后的组织及瞬时拉伸性能和700—900℃的蠕变持久性能,结果表明,合金由γ′的β相组成,其晶粒在温度低于1000℃时保持稳定;屈服强度在<600℃时也保持稳定;合金的高温塑性好,蠕变研究表明,该合金在700—900℃蠕变由位错攀移控制,其蠕变激活能为439kJ/mol,应力敏感系数为4.     

ANALYSIS OF THREE DIMENSIONAL HEAT TRANSFER OF COOLING COPPER PLATE IN THIN-SLAB CONTINUOUS CASTING MOLD

本文建立了薄板坯连铸结晶器铜板的三维传热数学模型，特别是对结晶器铜板冷面的水槽和背板部分采用了交替配置不同的边界条件处理，利用Visual Fortran语言自编程序计算结晶器铜板温度场。发现结晶器铜板热面温度呈现云层分布，冷面呈现冰凌状分布。分析了各种工艺参数（拉速、铜板厚度、冷却水流速等）对结晶器铜板温度场的影响。典型位置上的计算结果与现场测量数据符合较好，为优化生产工艺参数和结晶器设计提供重要的理论依据和实际参考数据。     

EXPERIMENTAL RESEARCH AND NUMERICAL SIMULATION OF MOLD TEMPERATURE FIELD IN CONTINUOUS CASTING OF STEEL

Mold is the heart of the continuous casting machine. Heat transfer and solidification in a water cooled mold are the most important factors during the continuous casting of steel. For studying the temperature distribution of a mold wall, a simulated apparatus of mold was designed and experiments were performed by it. The measured results indicated that the mold wall temperature approaches the temperature of cooling-water. An equivalent thermal-conductivity coefficient was proposed and deduced on the basis of the conclusion of the experiments. This coefficient was applied to solve the heat transfer between the melt and cooling water, and to characterize the heat transfer capacity of the mold. By this equivalent thermal-conductivity coefficient, it is very easy and convenient to numerically simulate the solidification process of continuous casting. And the calculation results are in agreement with the experiments. The effects of casting speed and water flow rate on the mold temperature field were also discussed.