Cu对Al-Li合金组织结构与性能的影响SCIEI

本文研究了3种Cu/Li比的Al-Li-Cu-Zr合金的时效析出组织及其性能。结果表明,实验合金时效由两级硬化过程所组成,其中第一级硬化是δ′相(3号合金为δ′+T_1相)强化而引起;第二级硬化是由于δ′+T_1(3号合金为δ′+T_1+θ′)的复合强化作用。当T_1相板条与δ′相颗粒相遇时,δ′相逐渐被T_1相吞并。Cu/Li比增加,合金的强(硬)度上升,但塑性下降,拉伸断口由穿晶变为沿晶形式,这与高Cu/Li比合金中晶界析出平衡相有关。     

2091Al-Li合金的形变热处理SCIEI

研究了预冷变形和分级时效处理对2091型Al-Li合金显微组织和力学性能的影响。结果表明,固溶后8％预冷变形随后170℃,6h+190℃,4h双级时效可以使合金获得良好的强塑性配合。合金中主要强化相δ′(Al_3Li)适宜的粒度,第二强化相S′(Al_2CuMg)沿冷加工所造成的位错亚结构分散沉淀,晶界上平密相析出量的减少以及Δδ′无沉淀析出带(PFZ)的窄化,是这种合金强塑性改善的主要原因。     

快速凝固Al-Li合金超塑性的研究SCIEI

制备了急冷微晶铝锂合金并对其超塑性进行了研究。热机械处理使快凝铝锂合金获得超塑性。固溶+过时效+温轧+再结晶预处理的铝锂合金最大延伸率为585％,最佳超塑变形条件是:温度540℃,应变速率1.67×10^(-2)s^(-1)。观察分析了预处理中的组织变化和超塑变形中的空洞。超塑断裂主要因为空洞形成、长大、绕晶粒联接所致。     

Al-Li合金断裂与微观结构变化的关系

用三维金相和扫描电镜方法观察并分析了Al-Li合金的断裂类型与微观组织结构的关系,阐明了不同断裂类型的内部联系及其随再结晶过程的变化规律,并从微观结构、能量和几何的观点出发,解释了不同类型断裂的成因、过程和特征.     

8090Al-Li合金晶间腐蚀与剥落腐蚀性能研究SCIEI

本文研究了8090Al—Li合金的点蚀、晶间腐蚀和剥落腐蚀性能,探讨了热处理制度对耐腐蚀性能的影响。结果表明:Al-2.79Li-1.3Cu-0.7Mg-0.12Zr合金自然时效态抗晶间腐蚀和剥落腐蚀性能最佳,峰时效状态耐腐蚀性能最差,欠时效比过时效略好。显微组织观察表明合金的耐蚀性能与显微组织密切相关,峰时效条件下,粗大T_2相连续分布于晶界上,它的电位比基体电位低因此晶界构成阳极通道,从而使合金耐蚀性能恶化。     

Al-Li合金分级时效的微观相场模拟

基于离散格点形式的微观相场动力学扩散方程，以Al-10at％Li合金为对象，对3种不同的时效工艺进行计算模拟。结果表明，对于该合金，采用137℃预时效＋190℃终时效工艺比另2种时效工艺获得的组织更均匀，颗粒更细化、弥散度更高。Al-10at％Li合金的单级时效和分级时效的沉淀相δ’（Al3Li）由失稳分解＋形核长大的混合方式形成。分级时效可以有效地提高有序相的体积分数和颗粒密度。     

Mn-Cu合金马氏体相变与沉淀的内耗SCIEI

用倒扭摆内耗仪测量了含Mn量92.8及90wt-％两种Mn-Cu合金在—100—400℃温度范围的内耗温度谱。除在-40及160℃附近是熟知的孪晶界面弛豫峰和马氏体相变峰(P_?峰)外,还新发现40℃内耗峰(P_2峰)是Spinodal组分分解形成的贫Mn区内的马氏体相变内耗峰。200℃附近的弛豫峰(P_3)与a-Mn的沉淀物有关,激活能为1.1eV。340℃弛豫峰(P_4)是在430℃真空时效过程中逐渐形成的,激活能为1.47eV。     

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。     

Ce对2090Al-Li合金疲劳裂纹扩展行为的影响SCIEI

研究了7075,2090和2090+Ce合金的疲劳裂纹扩展行为。2090合金的名义疲劳裂纹扩展抗力优于7075合金,归因于其高的裂纹闭合效应,但其本征疲劳裂纹扩展抗力低于7075合金。在2090合金中添加微量Ce,可同时提高其本征疲劳裂纹扩展抗力和裂纹闭合效应,故其名义疲劳裂纹扩展抗力大幅度提高。     

形变热处理对Al-Li合金组织和性能的影响

研究了形变热处理对2091型Al-Li合金显微组织和力学性能的影响,结果表明,固溶＋8％变形＋双级时效可以使合金获得良好的强塑性配合。合金中主要强化相δ（Al3Li）适宜的粒度、析出相S’（Al2CuMg）分散沉淀、晶界上平衡相析出量的减少以及δ＇无沉淀析出带（PFZ）的窄化,是合金强塑性改善的主要原因。     

PRECIPITATION IN BINARY Al-Li ALLOYS

Studies were carried out on the precipitation in two sets of binary Al-Li alloys by means ofhardness tests,DSC analyses and TEM observations.When the alloys were aged for constanttime,a peak appeared on the plot of temperature dependence upon their hardness in the rangeof low temperatures,and the endothermic dissolution peak was quite distinct on the DSCcurve also at low temperatures.These are believed that an Li-rich GP zone formed in the al-loys aged at low temperatures,but no more GP zone if aging at elevated temperatures.Thehardness of the alloys raises rapidly with coarsening of δ′-phase grains.The two endothermicpeaks of δ′ dissolution on the DSC curve relate to the structural adjustment at twice of the δ′precipitation.The equilibrium δ-phase,being of higher thermal stability,nucleates and growsdirectly from the supersaturated solid solution with the aid of the gram boundary.     

MICROSTRUCTURAL VARIATION AND FRACTURE MODES IN Al-Li ALLOYS

The correlation between the diverse fracture modes and the microstructural variation withrecrystallization in the Al-Li alloys under heat treatment was observed by means of triplanaroptical and scanning electron microscopy.The growth,propagation and feature of their frac-tures were described from the viewpoint of microstructure,energy and geometry.     

GRAIN-BOUNDARY PRECIPITATION UNDER IRRADIATION IN DILUTE BINARY ALLOYS

Irradiation-induced grain boundary segregation of solute atoms frequently bring about grain boundary precipitation of a second phase because of its making the solubility limit of the solute surpassed at grain boundaries. Until now the kinetic models for irradiation-induced grain boundary precipitation have been sparse. For this reason, we have theoretically treated grain boundary precipitation under irradiation in dilute binary alloys. Predictions of γ' -Ni3Si precipitation at grain boundaries are made for a dilute Ni-Si alloy subjected to irradiation. It is demonstrated that grain boundary silicon segregation under irradiation may lead to grain boundary γ'-Ni3Si precipitation over a certain temperature range.     

微量Y对Al—Li合金的析出相和力学性能的影响

研究了Y(0.1、0.5wt-％)对Al-Li-Cu—Mg—Zr合金析出相与拉伸性能的影响结果表明:Y可使铸态合金晶粒细化:促进β′(Al_3Zr)相析出:抑制δ′(Al_3Li)相的长大速度:使S′(Al_2CuMg)相的分布均匀化.添加0.1％Y能改善合金塑性而不降低强度:添加0.5％Y可使强度提高而塑性不降低     

ON SPINODAL BOUNDARIES OF Al-Li ALLOYS

ＯＮＳＰＩＮＯＤＡＬＢＯＵＮＤＡＲＩＥＳＯＦＡｌ－ＬｉＡＬＬＯＹＳ￥ＷＥＩＹｉｎｇｈｕｉ;ＷＡＮＧＸｉａｏｔｉａｎ（ＳｃｈｏｏｌｏｆＭａｔｅｒｉａｌｓＳｃｉｎｃｅａｎｄＥｎｇｉｎｅｅｒｉｎｇ,Ｘｉ＇ａｎＪｉａｏｔｏｎｇＵｎｉｖｅｒｓｉｔｙ,Ｘｉ＇ａｎ...     

EFFECT OF PRECIPITATION HARDENING ON SERRATED FLOW CHARACTERISTICS IN AN Al－Li ALLOY

ＥＦＦＥＣＴＯＦＰＲＥＣＩＰＩＴＡＴＩＯＮＨＡＲＤＥＮＩＮＧＯＮＳＥＲＲＡＴＥＤＦＬＯＷＣＨＡＲＡＣＴＥＲＩＳＴＩＣＳＩＮＡＮＡｌ－ＬｉＡＬＬＯＹＥＦＦＥＣＴＯＦＰＲＥＣＩＰＩＴＡＴＩＯＮＨＡＲＤＥＮＩＮＧＯＮＳＥＲＲＡＴＥＤＦＬＯＷＣＨＡＲＡＣＴＥ...     

AGING PRECIPITATION OF Cu-Zr AND Cu-Zr-Si ALLOYS AND AFFECTED BY COLD WORKING

The hardness and electrical conductivity of Cu-Zr and Cu-Zr-Si alloys varying with differ-ent aging regimes were measured and the factors influencing the electrical conductivity wereanalysed.It is believed that a little Si can refine the precipitates and improve the resistance tosoftening.The improvement of materials properties by aging and the effect of cold work werealso discussed.     

铝锂合金的合金化与微观组织演化

评述了铝锂合金的发展历程和应用以及我国铝锂合金研究所取得的成果。阐述了第3代铝锂合金的成分、微观组织和性能特点,讨论了合金化元素在调控铝锂合金微观组织进而改善性能方面的作用。大量研究表明,这些合金化元素可改变铝锂合金中原有析出相的大小、形状、分布,或刺激新强化相的析出,也可以细化晶粒、控制再结晶和晶粒取向。时效析出过程的本质和动力学在很大程度上取决于合金化元素之间的交互作用和合金原子的团簇化过程。