Effect of low frequency electromagnetic field on microstructures and macrosegregation of horizontal direct chillcasting aluminum alloy

1　INTRODUCTIONTheDC(directchill)castingprocessisawell estab lishedproductionrouteforaluminumalloyandhasbeenclassifiedintoVDC(verticaldirectchill)castingandHDC(horizontaldirectchill)castingprocess .AscomparedwithVDCprocess ,HDCprocesshasmanyadvantagessuchaslowerinvestmentcost,higherflexibility ,longercastingtimes[13] .However,HDCprocesshassomechar acteristictechnicalproblemsduetogravitydifferencebe tweentopsurfaceandbottomsurfaceathorizontalportion ,which ,inturn ,resultsininhomogen…     

Mn含量对高饱和度Al-8Zn-1.8Mg-1.4Cu合金强度的影响

通过透射电镜(TEM与HRTEM)、室温拉伸测试、JMatPro模拟等手段,研究了0.4%与0.8%的Mn对高饱和度Al-8Zn-1.8Mg-1.4Cu合金锻件抗拉强度、屈服强度的影响。结果表明,当合金中含有0.4%与0.8%的Mn时,合金抗拉强度分别达到545、553MPa,较基体合金分别提高7.9%和9.5%,屈服强度分别达到448、469MPa,较基体合金分别提高16.3%和17.4%;向Al-8Zn-1.8Mg-1.4Cu合金中添加Mn元素,经过固溶时效热处理后合金中形成Al_6Mn析出相,Al_6Mn析出相以棒条状存在于晶粒内外,其数量随Mn含量提高而增多;固溶时效后,Al_6Mn析出相与铝基体以非共格形式存在,以弥散强化方式提高合金强度;另外,Mn原子会置换铝基体中的Al原子,导致面心立方铝基体晶格发生膨胀、晶格常数变大,产生晶格畸变,实现固溶强化。     

Deformation mechanism maps of magnesium lithium alloy and their experimental application

Deformation mechanism maps for binary Mg-(8-9) Li(mass fraction,%) alloy at 423-623K were constructed in order to elucidate the internal meaning of mechanical experimental data at elevated temperatures,The models and data source used for constructing maps and constructe results are presented.It is determined through comparison of mechanical experimental data with constructed deformation mechanism maps that the dominant deformation mechanism for such alloy at 423-623K is lattice diffusion controlled grain boundary sliding.The difference of such deformation mechanism maps from former ones in that dislocation quantity inside the grains participates in the model calculation,which reveals the dislocation features of different deformation mechanisms.     

Mechanical relationship in steel-aluminum solid to liquid bonding

1　INTRODUCTIONThecurrentproductsofsolidsteelplatetoliquidaluminumincludehot dipaluminizingsteelplate[1,2 ]andsteel aluminumsolidtoliquidbondingplatemain ly[3,4 ] .Theyarewidelyusedinornament ,machin ery ,automobileandnavigationfield .Fortheseprod ucts ,theinterfacialmechanicalpropertyiscrucial;itdeterminesthequalityandapplicationoftheseprod ucts .Thelargertheinterfacialmechanicalproperty ,thewidertheapplicationoftheproduct .Theinterfacialmechanicalpropertyisdeter minedbyinterfacialstruct…     

两种Al-Mg合金超塑性能的对比研究

对Al－Mg－Li－Zr（01420）合金和Al－Mg－Mn－Zr（LF6）合金超塑性能进行了对比研究，发现Li元素的加入可以显著提高Al-Mg合金的超塑性能。     

A356合金半固态充型过程的数值模拟

利用ANSYS有限元软件分别对A356合金轮毂压铸件在不同充型温度、压射速度条件下,半固态浆料的流动及其传热现象进行了耦合数值模拟。通过模拟结果的分析,考察了充型温度及压射速度对充型过程中半固态浆料流动及温度分布的影响,发现当充型温度为590℃、压射速度为5m/s时,半固态浆料充型效果最理想,有利于获得组织致密的成形件,为A356合金半固态压铸成形工艺的制定和优化提供了依据。通过试验,对数值模拟所获得的工艺参数进行了验证。     

AlSi7MgBe合金半固态挤压成形件热处理工艺的优化

采用人工神经网络的方法,研究了固溶时效工艺参数对AlSi7MgBe合金半固态挤压成形件热处理性能的影响,建立了AlSi7MgBe合金半固态挤压成形件热处理工艺制度的人工神经网络模型,并对热处理工艺进行了优化,结果表明,当545℃固溶4h,178℃时效10h,成形件具有最优力学性能Rm=325MPa,A5=14.6%。     

热处理对低频电磁铸造2024铝合金力学性能的影响

通过试验研究了均匀化热处理和人工时效处理对普通DC铸造和低频电磁铸造2024铝合金力学性能的影响。结果表明,随均匀化时间延长,两种试样均呈抗拉强度降低、伸长率增加的趋势。低频电磁铸锭伸长率的变化幅度大于普通DC铸锭。试验还进行了两种铸锭经轧制变形后的人工时效处理,普通DC铸造和低频电磁铸造的铝合金时效后的硬度都随时效时间延长,先升高、后降低,且低频电磁铸造2024铝合金时效后的硬度高于普通DC铸造2024铝合金。电磁铸造2024铝合金的硬度经过10h处理后达到峰值,普通DC铸造铝合金到达时效峰值的时间则有所滞后。     

镁合金电磁铸造中搅拌频率的确定

通过镁合金电磁铸造过程模拟，分析了镁合金电磁铸造过程中电磁搅拌对熔体流动和温度分布的影响。结果表明，当镁合金电磁铸造的搅拌频率为10Hz时熔体温度场分布比较合理。     

金属半固态加工

半固态加工是生产形状复杂的近终形产品的一种新方法。从半固态金属的基本物理性能,阐述了半固态金属浆液的制备、半固态金属的成形、半固态加工产品的机械性能、应用及未来发展趋势。