Microstructure and properties of new Mg-Li-Zn wrought alloys

Cold-rolling workability, heat treatment characteristics and mechanical properties of Mg-5%-22 % Li-2 % Zn(mass fraction) wrought alloys were studied. Density of alloys is between 1.19 and 1.62 g/cm3. The limit of reduction for cold rolling of the β phase alloys at 16% and 22%Li exceeds 90% at room temperature. The properties and microstructures of Mg-Li-Zn alloys were studied, which were homogenized, cold rolled, then annealed at different temperatures. Recrystallization behaviors of the alloys were investigated through microstructures observing and hardness measuring. The results show that the cast billets are suitable for rolling after homogenization at 573K for 12 h for Mg-9Li-2Zn-2Ca alloy and at 523K for 24 h for Mg-9Li-2Zn-2Ca alloy. The cold rolled plates were completely recrystallizated by annealing at 573K for 1 h.     

Microstructure and properties of new Mg-Li-Zn wrought alloys

1 IntroductionMagnesium-Lithiumalloyis the lightest alloy at present .It is one of ultra-light weight alloy systemswith highintensity .It is as light as engineering plastics ,but it has the properties of a metal such as highspecific rigidity ,i mpact ductility , good electrical and thermal conductivities , machining,electromagneticshielding,and shockproof etc .[1].In addition,it can be reclai med and reused,and don' t pollute environ-ment ,thus it is called a“green”alloy for 21st century .N…     

退火工艺对 FeCo软磁合金微观组织与力学性能的影响

对经退火热处理的FeCo软磁合金带材的力学性能进行了研究,同时对比了1J22合金和高强度FeCo合金冷轧带材在不同热处理温度下退火后的组织变化。结果发现：随着退火温度的上升,两种合金的强度均下降、晶粒的粒径均变大;在850℃时,1J22合金晶粒已经明显粗化,高强度FeCo合金晶粒有略微长大,但晶粒较均匀;在880℃时,两种合金晶粒均明显粗化,且不均匀。     

Al-RE中间合金对变形铝合金组织与性能的影响

本文以工业纯铝和混合稀土RE(Ce和La)为原料,制备出Al-8RE、Al-10RE和Al-15RE中间合金,并探讨了Al-RE中间合金对变形铝合金3102的细化机理。结果表明：Al-RE中间合金由α-Al、Al11RE3(Al11Ce3和Al11La3)、Ce和La组成,不同稀土含量Al-RE中间合金微观组织形貌不同,Al-8RE、Al-10RE和Al-15RE中间合金组织分别为亚共晶组织,伪共晶组织和过共晶组织,随稀土含量增加,Al-RE中间合金中Al11RE3相数量增多,尺寸增大;Al-RE中间合金对3102合金具有显著的细化效果,其中Al-10RE中间合金的细化效果最好;添加Al-RE中间合金可以提高产品性能,当添加10%RE时,性能提升最大。     

固溶和时效处理对铝热法制备Cu-Ti合金组织和性能的影响

Cu-Ti合金作为导电弹簧,互联接插件等重要元器件的制备材料,其大规模工业制备方法和热处理工艺仍是当前铜合金领域亟需开发和推进的重点。本文采用具有工艺简单、环保节能、成本低廉等优点的铝热法制备了Ti含量分别为1.0 wt.%、4.5 wt.%、10.0 wt.%,即成分区间较大的Cu-Ti合金,且进一步采用固溶和时效处理来调控合金的综合性能。结果表明时效态的Cu-1.0 wt.%Ti和Cu-4.5 wt.%Ti合金中Ti元素主要呈固溶状态,只有非常少量尺寸较小的析出相,而Cu-10.0 wt.%Ti合金中存在大量尺寸较大的Cu4Ti相析出。随着Ti含量的增加,合金的导电率有明显降低的趋势,而硬度和强度则呈现与之相反的趋势。对于成分相同的合金,相较于固溶状态,时效后导电率先略微下降然后上升,450 °C时效4 h后,三个成分合金的导电率均高于固溶态合金;450 °C时效2 h后,Cu-1.0 wt.%Ti和Cu-4.5 wt.%Ti合金均获得了硬度、强度和延伸率的最大值,Cu-10.0 wt.%Ti合金的硬度和延伸率也获得了极大值,其屈服强度和抗拉强度则是随着时效时间呈略微下降的趋势。     

热处理对铝硅基复合材料显微组织的影响

研究了热处理条件对铝硅基复合材料组织的影响。实验结果表明, 热处理能改善铸态下制得的铝硅基复合材料显微组织形态。热处理保温时间的适当增长可使MMC 组织变得细小。另外, 热处理温度与制作铸态MMC 的冷却速度的增大会导致MMC热处理后新相组织的产生, 这是由于冷却速度的增大导致共晶温度的下降引起的。     

Effect of strain rate on microstructure and mechanical properties of a Mg-9Li-2Zn alloy sheet

A two-phase Mg-9Li-2Zn alloy sheet is made by cold-rolling at room temperature, and the formability of it at room temperature is investigated in this study. Uniaxial tension tests are carried out for various strain rates between 0. 5 mm/min and 250 mm/min, and the microstructural changes during the tests are observed. The sheet has high formability at comparatively low strain rates. Maximum elongation amounts to 40%. However, ductility decreases with the increase of strain rate. Even at room temperature, the stress is also sensitive to the strain rate. There are many large dimples at comparatively low strain rates, and small dimples occur at high strain rates, it shows fine sub-grains come into being.     

退火时间对BAg30CuZnSn钎料合金组织和性能的影响

本文研究了在500℃条件下退火时间对(轧制态)BAg30CuZnSn钎料合金的组织和力学性能的影响。通过对钎料合金进行退火处理,组织观察、力学性能测试等,研究了退火时间对钎料的微观合金组织和力学性能的影响规律。结果表明：随着退火时间的增加,BAg30CuZnSn钎料合金的Cu基固溶体沿着轧制方向由长条状转变为片状且逐渐变得粗大,同时析出网状的Cu-Ag共晶组织,相边界逐渐变得清晰和完整;随着退火时间的增加,钎料合金的显微硬度值呈现出逐渐降低,且在未退火处理时取得最大值120.85Hv0.05,在退火时间为100h时取得最小值84.5 Hv0.05。     

热处理对2124铝合金热轧厚板组织与性能的影响

通过室温拉伸性能测试和DSC、TEM分析, 对2124铝合金40 mm厚板的热处理制度进行了研究。研究结果表明, 合金主要强化相为S'和θ'过渡相; 合金的适宜固溶温度为495～500 ℃, 固溶时间为80～100 min; 适当提高固溶温度或延长固溶时间, 合金中过剩相的溶解程度增大, 提高了合金的固溶程度, 从而提高合金的强度; 合金适宜的时效温度为185 ℃, 时效时间为12 h。     

冷变形与时效热处理对CuCrZr合金组织及硬度的影响

研究CuCrZr合金在不同形变量与时效热处理制度下的组织及硬度变化。结果表明,冷变形与时效热处理均能有效提高CuCrZr合金的硬度,固溶处理的CuCrZr合金冷变形后再经时效处理,叠加效果更加显著。时效处理温度在480℃时合金硬度呈现极大值。     

热处理工艺对超高强铝合金组织与性能的影响

通过硬度、拉伸性能测试, 金相、扫描电镜、透射电镜观察, X 射线衍射分析, 研究了热处理工艺对新型电磁铸造合金(Al-9.0Zn-2.5～2.8Mg-2.0～2.4Cu-0.1～0.15Zr-0.224Ag)显微组织和性能的影响。结果表明:合金的峰时效制度为120 ℃/24 h。在峰时效条件下, 合金的抗拉强度达到730 MPa, 屈服强度达到705 MPa, 延伸率为8.8 %。合金有显著的时效硬化特性, 其强化机制主要是沉淀强化, 合金的主要强化相为GP 区和η′过渡相。合金的断裂形式为微孔聚集型韧性断裂。     

固溶温度对Al-Cu-Mg-Ag合金显微组织与力学性能的影响

通过金相显微镜、透射电镜、扫描电镜和室温拉伸试验研究了固溶温度对Al-Cu-Mg-Ag合金显微组织与力学性能的影响。结果表明: 随着固溶温度提高(500~520 ℃), Al-Cu-Mg-Ag合金在190 ℃/2 h时效过程中析出的Ω相数量密度逐渐增加, 而且Ω相的大小更均匀, 从而导致合金的强度和热稳定性逐渐提高。热暴露(200 ℃/1 000 h)后, Ω相数量密度显著下降, 从而导致Al-Cu-Mg-Ag合金的强度大幅下降。在热暴露过程中, Ω相的直径方向增长速率远远大于厚度方向增长速率。     

低温均匀化对6082铝合金组织及性能的影响

通过OM、SEM、EDS、拉伸测试、硬度检测等方法,研究了低温均匀化热处理工艺对特定成分的6082铝合金铸锭组织及性能的影响。结果表明:当均匀化温度从350℃升高至450℃时,随着温度的升高晶界上的第二相(α-Al(FeMnCr)Si)分解越充分,晶内析出相(Mg2Si)析出越均匀;温度升高对应的力学性能也相应提升,其中抗拉强度及硬度在450℃/10 h时达到最大值为162.5 MPa和53.3HV,导电率在450℃/15 h时达到最大为48.63%IACS;相同均匀化温度下保温10和15 h,对6082铝合金的组织和力学性能影响不大。     

5083和7020变形铝合金加工图的研究

在动态材料模型理论基础上,对5083和7020两种典型变形铝合金的加工图进行研究分析,结果表明:5083铝合金适宜加工区的温度为450～500℃、应变速率为0.005～0.1s-1;7020铝合金适宜加工区的温度为450～550℃、应变速率为0.001～O.1s-1.同时通过选取7020铝合金在不同加工条件下的压缩试样...     

Effect of strain rate on microstructure and mechanical properties of a Mg-9Li-2Zn alloy sheet

1 IntroductionMagnesium-Lithiumalloyis thelightest alloy at present .Its properties are as follows :high specific ri-Fig .1 The phase diagramof Mg-Li alloygidity ,i mpact ductility , machining,electromagnetic shielding,and shockproof etc .[1 ,2].In additionit can be reclai med,reused,and don't pollute environment ,thus it is called a“green”alloyfor 21st century .Magnesiumis a hexagonal closepacked metal and has poorformability . However ,it is well knownthat the addition of lithi-umto mag…     

Effect of strain rate on microstructure and mechanical properties of a Mg-9Li-2Zn alloy sheet

A two-phase Mg-9Li-2Zn alloy sheet is made by cold-rolling at room temperature, and the formability of it at room temperature is investigated in this study. Uniaxial tension tests are carried out for various strain rates between 0. 5 mm/min and 250 mm/min, and the microstructural changes during the tests are observed. The sheet has high formability at comparatively low strain rates. Maximum elongation amounts to 40,. However, ductility decreases with the increase of strain rate. Even at room temperature, the stress is also sensitive to the strain rate. There are many large dimples at comparatively low strain rates, and small dimples occur at high strain rates, it shows fine sub-grains come into being.     

铸态和固溶态Mg-Sn二元合金的组织与力学性能

分析了铸态和固溶态Mg‐xSn（x＝2．18～6．54）合金的组织,测试了其拉伸力学性能、硬度及冲击韧性．结果表明,随着Sn含量的增加,铸态组织中粗大树枝晶状α‐M g逐渐细化,M g2 Sn相逐渐增多,并且趋于连续网状分布于晶界处．室温下合金铸态拉伸力学性能及冲击韧性表现为先提高后降低,具有最佳性能的Mg‐3．52Sn合金的抗拉强度σb 、延伸率δ和冲击韧性值αnK分别为151 MPa ,12．5％和10 J／cm2;高温（423 K）时σb和δ先分别逐渐提高至Mg‐3．52Sn合金的87 MPa和19．0％,经略有降低后又分别逐渐提高至Mg‐6．54Sn合金的92 MPa和15．5％．经固溶处理后,Mg2Sn相完全固溶于α‐Mg基体中;室温下拉伸力学性能有所提高,而高温下拉伸力学性能基本保持不变;在Sn含量低和高时冲击韧性分别降低和提高．     

固溶处理对Al-Li-Cu-Mg-Ag-Zr合金组织与性能的影响

通过力学性能、电导率测试和差示扫描量热法(DSC)、能谱分析(EDX)及光学显微镜(OM)、扫描电镜(SEM)、透射电镜(TEM)观察, 分析研究了固溶处理对Al-Li-Cu-Mg-Ag-Zr合金组织与性能的影响。结果表明: 当固溶时间为30 min时, 随固溶温度升高, 合金的拉伸强度和硬度先升高后降低, 520 ℃固溶温度下合金的力学性能最好; 520 ℃下, 随固溶时间的延长, 合金力学性能也呈现出先升高后降低的趋势; 520 ℃/30 min固溶处理的合金能获得最佳时效组织模式, T1相数量多、尺寸细小、弥散分布, 合金的综合力学性能最佳, 在此固溶制度下合金的断裂机制呈现穿晶断裂和沿晶分层断裂的混合断裂模式; 固溶温度为525 ℃时合金有局部过烧现象。     

制备工艺对Mo-Cu合金组织性能的影响

Mo-Cu合金具有高的导热系数和低的热膨胀系数,被广泛用作热沉材料和电子封装材料.本文介绍了Mo-Cu合金的几种制备方法,并对其优缺点进行了对比分析.结果表明采用化学镀+液相烧结法、熔渗以及熔渗+热压+二次烧结制得的Mo-Cu合金性能较优,其致密度大于99%,组织分布更均匀、细小,综合性能最好.