轧制和热处理对Mg-11Li-3Al-1.5Si-1.5Nd合金组织与力学性能的影响

通过光学显微镜、扫描电镜、能谱分析及力学性能测试等手段,研究轧制和热处理工艺对Mg-11Li-3Al-1.5Si-1.5Nd合金板材组织和力学性能的影响,探讨其析出相在合金中的作用。结果表明,铸态合金经过均匀化处理后,汉字形貌的Mg2Si相溶入基体,其综合性能大幅下降。但在随后的轧制过程中,合金的力学性能得到双重提升。合金板材经过淬火处理后,晶粒非常细小,主要由β-Li基体和沿轧制方向分布的少量颗粒状Mg17Al12相组成,抗拉强度最大可达344.3MPa。而退火处理后,其仍保留轧制态的组织,但随着退火温度的升高,析出的白色α-Mg相逐渐减少,板材的抗拉强度略微下降,而塑性则呈先升后降再升高的趋势,其中220℃×1h退火板材的塑性最好,其伸长率为73.1%。     

稀土钇对铸态Mg-8Li-3Al-3Zn合金显微组织和力学性能的影响

镁锂(Mg-Li)合金是现今最轻的金属结构材料,在航空航天及交通运输等领域具有重大的应用价值.但铸造镁锂合金绝对强度低限制了其发展和应用.在Mg-Li二元合金中添加铝(Al)、锌(Zn)和稀土元素钇(Y)三种强化元素制备Mg-Li-Al-Zn-Y五元铸态镁锂合金来提高镁锂合金的力学性能.利用X射线衍射仪(XRD)、扫描...     

热轧及退火Mg-5Li-1Al板材的组织及力学性能演变

Mg-5Li-1Al 合金板材在热轧后分别经150℃和300℃退火30分钟。本文研究了热轧及退火态Mg-5Li-1Al板材的微观组织、力学性能及织构,并且讨论了其塑性变形机制。结果显示,退火态板材显示出了弱的织构和均匀的再结晶组织,其晶粒尺寸大约为15μm。随着退火温度的升高,合金板材的延伸率在逐渐提升,而抗拉强度、屈服强度、屈强比在减小,这些都对合金的成形性能非常有利。经300℃退火30分钟的合金板材表现出最好的力学性能,其原因在于Li元素的添加和退火温度的升高。     

Y对Mg-8Li-3Al合金组织和性能的影响

采用真空感应熔炼技术制备了Mg-8Li-3Al-xY（x=0.5,1.0,3.0）合金。研究稀土Y对Mg-8Li-3Al合金组织和性能的影响。结果表明：在Mg-8Li-3Al合金中加入稀土Y,α（Mg）相被明显细化和球化,合金中生成了Al2Y相,添加w（Y）=0.5%-1%后,合金强度得到提高。     

Sn对Mg-8.5Li-3Al合金组织和性能的影响

采用真空感应熔炼技术制备了Mg-8.5Li-3Al和Mg-8.5Li-3Al-1Sn合金,研究Sn对Mg-8.5Li-3Ai合金组织和性能的影响,结果表明,Sn在Mg-Li-Al系合金中主要以颗粒状Mg2Sn化合物的形式存在于β(Li)相中,Mg2Sn颗粒对Mg-Li-Al合金可以起到第二相强化作用.     

电磁搅拌对Mg-8Li-3Al合金显微组织和力学性能的影响

研究了不同强度的电磁搅拌对Mg-8Li-3Al合金显微组织和力学性能的影响.结果表明,电磁搅拌能改善凝固过程的传热传质,细化枝晶,提高合金的抗拉强度、伸长率和硬度.当施加的电磁场电压为100 V时,Mg-8Li-3Al合金的显微组织细小均匀,室温抗拉强度、伸长率和硬度(HB)分别达到212.9 MPa、10.5%和71.3,合金的组织和力学性能达到最佳.     

热处理对Mg-7.28Li-8.02Y合金显微组织和力学性能的影响

用真空熔炼、真空热处理方法研究了超轻Mg-7.28Li-8.02Y合金的显微组织和力学性能,以及热处理工艺对该合金显微组织和力学性能的影响规律.结果表明,铸态Mg-7.28Li-8.02Y合金主要由β(Li)相基体和α(Mg)相以及沿晶分布呈网状结构的γ(Mg24Y5)相组成.对铸态Mg-7.28Li-8.02Y做固溶热处理后发现,随着淬火温度由300 ℃升高至500 ℃,Mg及γ(Mg24Y5)相在β相中的固溶程度增加,合金淬火硬度增加,γ(Mg24Y5)相呈圆球状均匀分布,其共同作用使合金抗拉强度大幅度提高;但150 ℃时效后,一方面有晶粒长大,另一方面长时间时效使Mg在β相中固溶度降低,α相沿β相晶界析出,导致合金硬度、强度及塑性有所下降.     

退火工艺对Mg-8Li-3Al-1Y镁锂合金组织和力学性能的影响

本文对冷轧态Mg-8Li-3Al-1Y镁锂合金进行了不同的退火工艺试验,并对不同退火工艺试验后的试样进行了显微组织观察和室温拉伸试验。结果表明,在退火处理过程中发生静态再结晶和α相球化行为,在360℃退火100 min时,合金发生了脱锂现象。同时得到了最佳的退火工艺制度为360℃×70 min,此时屈服强度、抗拉强度和延伸率分别为216.29 MPa、182.66 MPa和21.05%。     

Mg-14Li-3Al-1Y-0.8Zr-0.4Sc合金组织及不同轧制变形量对其力学性能的影响

镁锂合金材料在航天航空领域具有重要应用价值.探究不同轧制变形量对Mg-14Li-3Al-1Y-0.8Zr-0.4Sc合金力学性能的影响,为进一步获取质量更轻、力学性能更优的材料研制工艺奠定基础.利用光学显微镜(OM)、扫描电子显微镜(SEM)和能谱分析(EDS)表征铸态合金微观组织和第二相类型.通过显微维氏硬度计和室温...     

Al-Ti-C中间合金对Mg-8Li-3Al合金组织和性能的影响

通过液固反应制备了含TiC和Al4C3相的Al-Ti-C中间合金,并利用OM、XRD、SEM和EDS等研究了Al-Ti-C 中间合金对Mg-8Li-3Al合金显微组织和力学性能的影响.结果表明,Al-Ti-C中间合金的最佳加入量为1.0％;加入量为1.0％时,粗大的α相树枝晶变成颗粒状,并且α相变得更加细小圆整,合金的抗拉强度和伸长率分别达到199.28 MPa和14.60％.     

Effect of Nd content on microstructure and mechanical properties of as-cast Mg-12Li-3Al alloy

In order to improve the mechanical properties of Mg-Li alloy with single β phase structure, Mg-12Li-3Al-xNd(x=0.3, 0.7, 1.1, 2.0wt.%) alloy was prepared. Subsequently, the as-cast microstructure and mechanical properties were observed and tested. The results showed that the structure of Mg-12Li-3Al-xNd(x=0.3, 0.7, 1.1, 2.0wt.%) as-cast alloy was composed of β phase matrix and Al_2Nd, Al_(11)Nd_3, MgLiAl_2, Al_4Li_9 and AlLi phases. With the increase of Nd content in the alloy, the Al-Nd intermetallic compounds have a trend to change from needle-like Al_(11)Nd_3 to granular Al_2Nd. The hardness of as-cast Mg-12Li-3Al-xNd(x=0.3, 0.7, 1.1, 2.0wt.%) alloy was stable at room temperature. The tensile strength of Mg-12Li-3Al-1.1Nd was as high as 180 MPa, the elongation rate of Mg-12Li-3Al-0.7Nd reached 53.7%, and the comprehensive mechanical properties of Mg-12Li-3Al-2.0Nd was the best. PLC phenomenon occurred during the tensile process of the alloys at room temperature. Therefore, the β-based Mg-Li alloy with good plasticity as well as enhanced strength can be obtained by a moderate addition of Nd and Al.     

Effects of Sc and Mn on microstructures and mechanical properties of Mg-Gd alloy

Two alloys of Mg-12.4Gd and Mg-12.5Gd-0.8Sc-1.4Mn were prepared. Hot extrusion and T5 heat treatment were conducted, and then the mechanical properties of the two alloys were tested at room and high temperatures. The effects of Sc, Mn on the microstructures of Mg-12.4Gd were investigated by optical microscopy, scanning electron microscopy and transmission electron microscopy. The results demonstrate that after hot-extrusion the alloying with Sc, Mn can efficaciously refine the grains of Mg-12.4Gd alloy; and increase the elongation at room and high temperatures after T5 heat treatment. But the strength at high temperature is not obviously improved.     

Effects of Ag addition on mechanical properties and microstructures of Al-SCu-0.5Mg alloy

The mechanical properties and microstructures of Al-8Cu-0.5Mg alloy with and without Ag addition were studied at both room- and elevated-temperatures. The results show that the alloy with Ag is strengthened by a homogeneous distribution of coexistent θ＇ and Ω precipitates on the matrix （001） and （111） planes, respectively, whereas the alloy without Ag by θ＇ precipitates only. The small size and high volume fraction of θ＇ and Ω precipitates in the Ag-containing alloy improve the tensile strength and yield strength, especially those at the elevated temperatures. However, it is also responsible for the decrease in elongation, compared with the alloy without Ag, which is due to the microcracks initiated from the inherent incompatibility between the particles and the AI matrix during deformation.     

Mg-2Nd合金的组织与力学性能

在铸钢坩锅中熔炼制备了Mg-2Nd二元镁合金,试样经不同热处理工艺处理后,测试合金的室温拉伸性能,采用光学显微镜（OM）、扫描电镜（SEM）及透射电镜（TEM）观察合金的显微组织,通过X射线衍射法（XRD）和能谱分析（XEDS）及选区电子衍射花样进行合金中的物相鉴别和微观成分分析。结果表明：Mg-2Nd合金的铸态组织由α-Mg基体和呈离异共晶形貌的Mg12Nd相组成;热挤压后,Mg12Nd相沿挤压方向呈纤维或颗粒状分布;挤压过程中发生动态再结晶,合金的抗拉强度（σb）由铸态的148.8 MPa提高到挤压态的210.2 MPa,伸长率（δ）由铸态的2.8%提高到挤压态的19.9%;热挤压和热轧成形的Mg-2Nd合金,直接时效T5（extruded、rolled）处理能产生形变强化和时效硬化双重作用,其中T5（rolled）态合金σb高达276.4 MPa,δ较热轧态提高了64%;T5（rolled）态组织中出现了β′和β沉淀,尺度均在50 nm左右,对合金产生了明显的时效强化作用。     

钆对Mg-8Li-4Zn-xGd合金铸态组织与力学性能的影响

采用锂盐熔剂保护熔铸Mg-8Li-4Zn-xGd(x=1,3,5)合金铸锭,研究钆含量对铸态合金组织和力学性能的影响。结果表明:Mg-8Li-4Zn-xGd合金基体由α-Mg(HCP)和β-Li(BCC)双相构成。随着钆含量的增加,Mg₅Gd共晶相和Zn₁₂Gd化合物相逐渐连成网状,将基体α+β双相隔离成20～40μm的等轴状或类似于铸铁中的共晶团状,可有效细化α-Mg相和连续的β-Li相;组织中大颗粒Mg₂Zn₁₁相弥散分布在β-Li相内,Mg₅₁Zn₂₀相分布在α-Mg晶界处;锌元素还可以在β-Li相中析出细小弥散分布的MgZn相,其数量随钆含量的增加而增加,可直接弥散强化β-Li相。此外,锌和钆对合金硬度的影响较大,随着钆含量的增加,合金的抗拉强度提高,但伸长率降低。     

Effects of Ce and Ti on the microstructures and mechanical properties of an Al-Cu-Mg-Ag alloy

1. Introduction Heat-treated aluminum alloys are required for several structural applications. Several efforts have been made to improve the mechanical properties of the alloys that are currently in use and also to de-velop a novel series of alloys. The approaches used are: alloy modification, or processing modification, or both. The strength of aging-hardenable alloys such as Al–Cu–Mg series relies upon the strength-ening precipitates that are formed during aging after quenching. The agin…     

Effects of Ag addition on mechanical properties and microstructures of Al-8Cu-0.5Mg alloy

1 Introduction Heat-treatment aluminum alloys are required for many structural applications. And great efforts have been made to either improve the mechanical properties of the alloys currently being used or develop a completely new alloy series. The approaches adopted are either alloying modification, or processing modification, or both. The strength of aging-hardenable alloys such as Al-Cu-Mg series relies upon strengthening precipitates that form during aging after quenching. The aging s…     

Effects of erbium on microstructure and mechanical properties of as-cast Mg-7Zn-3Al alloy

Mg-7Zn-3Al-xEr(x=0.1,0.4,0.7) magnesium alloys were prepared by permanent mould casting.The effects of rare earth element of erbium on the microstructure and mechanical properties of as-cast Mg-7Zn-3Al alloy at both room temperature and elevated temperatures were investigated with optical microscopy,scanning electron microscopy/energy dispersive X-ray spectroscopy,differential scanning calorimetry,and tensile testing.The results show that the quasi-continuous grain boundary networkedτ(Mg_(32)(Al,Zn)_(49)...     

Effects of yttrium on microstructure and mechanical properties of Mg-6Al magnesium alloy

Since Y has a great solid solubility in magnesium alloys, it helps enhancing the heat-resistant property of magnesium alloys. The effects of Y on microstructures and mechanical properties of Mg-6Al alloy have been studied in this work. The results show that Y addition refines grains of Mg-6Al alloy, and reduces the amount of the Mg 17 Al 12 phase. At the same time, the high melting-point Al 2 Y phase particles are formed. According to the mathematical model of the two-dimensional lattice misfit proposed by Braffit, it is believed that the Al 2 Y particles can serve as the nucleation sites for α-Mg. After T6 treatment, both elongation and ultimate tensile strength of Mg-6Al alloy at the room temperature and high-temperature increased firstly and then decreased, with increasing Y addition. The peak mechanical properties were achieved in the Mg-6Al-1.2Y alloy system. Y addition appears to change the fracture characteristic of Mg-6Al alloy. With 1.2wt%Y, the fracture surface of the alloy showed a lot of dimples and tearing ridges which connected the microscopic dimples and the fracture is mixed fracture of quasi-cleavage and ductile fracture.     

镧对Zn-22%Al减振合金组织和力学性能的影响

通过测试抗拉强度的自然时效、人工时效曲线,采用光学显微镜、透射电镜及扫描电镜的观察,研究了微量La对Zn-22%Al减振合金显微组织和力学性能的影响.结果表明La具有细化Zn-22%Al合金的组织并阻碍时效时晶粒长大和等轴程度降低的作用;在低于温轧温度(80?℃)下时效时,加La和不加La的Zn-22%Al合金的室温力学性能保持不变;La可提高Zn-22%Al合金的强度以及时效时力学性能的稳定性.