高强高导铜合金合金化机理

通过对Cu-Cr-Zr系和Cu-Fe-P-Ag系两种高强高导铜合金框架材料合金成分的分析, 获得如下结论 1) 利用双相析出强化, 可以改善析出相的形态和析出过程, 也是获得高强高导铜合金的有效途径; 2) 固溶0.1%Ag元素, 通过Ag元素与其他固溶元素的交互作用, 减少基体内对导电率影响较大的元素溶入, 可改善材料的导电性和强度; 3) 通过对Cu-Fe-P-Ag系合金成分的分析, 提出了铜合金多元固溶体微观畸变累积假说, 利用此假说, 可有效地指导高强高导铜合金基体成分设计.     

Mg含量和冷速对Mg-Cu-Zn-Y非晶复合材料微观结构及腐蚀行为的影响

采用水冷铜模法和水淬法制备得到Mg65+x(Cu0.66Y0.34)30-xZn5(x=5,10,15)非晶及其复合材料。并通过XRD、SEM对材料结构进行表征,研究Mg含量和冷却速度对样品微观结构的影响。结果表明:由水冷铜模法得到的x=5样品为单一非晶,x=10和15样品是由非晶相与Mg固溶体相组成的非晶复合材料。而利用冷速较低的水淬法得到的样品为非晶复合材料,其主要由Mg,Mg2Cu,MgZnY和非晶相组成。通过研究合金在NaCl中性溶液中的腐蚀行为,发现随着Mg含量的增加,样品的耐腐蚀性能有所下降。并且对于同成分的合金,由冷速较快的水冷铜模法得到的样品耐蚀性相对较好。     

合金元素对Au的强化效应与应用

本文讨论了二元Au合金系中富Au端相图特征，合金元素在Au合金中分布及强化与脆化倾向性，分析了合金元素对Au的固溶强化参数和没淀强化参数，轻金属（尤其是Be)具有最高固溶强化参数，Ti具有最高沉淀强化参数；稀土金属兼具高的固溶强化参数和沉淀强化参数，是强化Au与Au合金的重要合金元素，讨论了某些实用Au合金的强化机制。     

白铜基体低表面能复合膜的制备及其耐腐蚀性能研究

目的研究混合修饰构筑白铜超疏水表面的可行性及防腐性能。方法以白铜为基体,采用简单的化学刻蚀法,以硝酸银溶液作为刻蚀液,经肉豆蔻酸和十二硫醇的混合乙醇溶液修饰来制备超疏水白铜。采用接触角测量仪、XRD、FTIR、SEM、EDS对超疏水白铜表面性能和结构等进行了表征,并利用Tafel曲线和电化学阻抗谱研究低表面能复合膜的耐蚀性能。结果肉豆蔻酸和十二硫醇的疏水长链都组装到薄银层表面,其中肉豆蔻酸和薄银层的键合形式为双齿桥式复合模式,超疏水白铜表面形貌由微米级枝晶和纳米级乳突状结构组成,同时材料表面与水的接触角达到157.4°,表现出超疏水水平。此外,制备的超疏水白铜表面具有良好的化学稳定性和耐腐蚀性能,在水、有机溶液、3.5%Na Cl溶液中分别浸泡2 d,所有样品表面仍表现为超疏水水平。由Tafel极化曲线拟合参数计算可知,其缓蚀效率达到83.9%。结论以两种低表面能物质混合修饰来制备超疏水白铜表面的方法是可行且有效的,且该复合膜具有优良的耐腐蚀性能。     

Effect of laser surface treatment on corrosion and wear resistance of ACM720 Mg alloy

A creep resistant Mg alloy ACM720 was subjected to laser surface treatment using Nd:YAG laser equipped with a fiber optics beam delivery system in argon atmosphere. This treatment was found to be beneficial for the corrosion and wear resistance of the alloy. Long-term linear polarization resistance and Electrochemical Impedance Spectroscopy measurements confirmed that the polarization resistance values of laser surface treated alloy were twice as high as that for the untreated alloy. The improved corrosion resistance was attributed to the absence of the second phase Al₂Ca at the grain boundary, microstructural refinement and extended solid solubility, particularly of Al, in α-Mg matrix owing to rapid solidification. The laser treatment also increased surface hardness two times and reduced the wear rate considerably due to grain refinement and solid solution strengthening.     

Microstructure and Mechanical Properties of Multicomponent Aluminum Alloy by Rapid Solidification

Al₉₀Ni_2.5Ti_2.5La_2.5Mn_2.5 alloy with multicomponent alloying elements was prepared by rapid solidification. The hardness and the compression strength of the alloy reached 285 HV and 712 Mpa, respectively. The alloy exhibited good wear resistance, which was three times that of the conventional A309 aluminum alloy. The high strength and wear resistance of the alloy were attributed to the second-phase strengthening and the solid solution strengthening mechanisms.     

点焊电极用铜合金材料强化技术的研究现状

在现代工业中广泛应用的点焊电极用铜合金材料多为铬铜、铬锆铜和Al_2O_3弥散强化铜,主要因其导电性、导热性、高温强度、硬度和可加工性。综述了多种强化技术的机理和工艺,通过对基体进行固溶时效和形变强化处理,或进行深冷处理,或通过Al_2O_3、TiB_2、石墨、碳纳米管等对基体进行弥散强化,可以有效地提高铜合金性能。展望了点焊电极用铜合金的强化技术。     

Preparation and properties of W–Cu–Zn alloy with low W–W contiguity

The W–Cu–Zn alloy with a-brass matrix and low W–W contiguity was prepared by method of electroless copper plating combined with spark plasma sintering(SPS) method.The effects of process and parameters on the microstructure and mechanical properties of the alloy were investigated.The W–Cu–Zn alloy with a relative density of 96 % and a W–W contiguity of about 10 % was prepared by original fine tungsten particles combined with wet mixing method and SPS solid-state sintering method at 800 °C for 10 min.The microstructure analysis shows that Cu–Zn matrix consists of nano-sized a-brass grains,and the main composition is Cu_3Zn electride.The nano-sized Cu was coated on the surface of tungsten particles by electroless copper plating method,and the fairly low consolidation temperature and short solid-state sintering time result in the nano-sized matrix phase.The dynamic compressive strength of the W–Cu–Zn alloy achieves to1000 MPa,but the alloy shows poor ductility due to the formation of the hard and brittle Cu_3Zn electrides.The fine-grain strengthening and the solution strengthening of the Cu–Zn matrix phase are responsible for the high Vickers microhardness of about 300 MPa for W–Cu–Zn alloy.     

钛合金空蚀损伤及防护的研究进展

钛合金具有密度小、比强度高、耐蚀性好等优势,被广泛应用于诸多工程领域。由于钛合金存在表面硬度低、耐磨性差等缺点,导致其在过流部件中容易发生空蚀损伤,会降低钛合金构件的使用寿命,因此针对钛合金空蚀损伤行为及其防护措施的研究显得极为重要。概述了空蚀现象的作用机理和理论模型,详细介绍了材料自身的力学性能、表面状态、介质类型和溶液温度等对钛合金空蚀行为的影响,着重讨论了针对钛合金空蚀损伤的多种应对措施,如热处理、激光纹理加工、激光气体氮化、化学热处理、离子注入、添加缓蚀剂等技术,总结了相应方法提高钛合金抗空蚀性能的具体原因。其中,热处理技术通过改变钛合金自身的显微组织来提高其抗空蚀性能;激光气体氮化工艺可在钛合金表面形成硬质TiN相,以抵御空泡溃灭时的冲击;化学热处理技术在钛合金表面生成了致密的陶瓷层+固溶扩散层,缓解了空泡的溃灭能,延长了空蚀的孕育期;离子注入技术依靠注入离子在钛合金材料表面产生固溶强化、位错增值强化等效果,降低其空蚀损伤。最后对钛合金空蚀及防护研究的发展方向提出了展望。     

纯铜深层渗铝内氧化的组织及性能

为提高铜质件的耐热性和耐磨性,采用纯铜深层渗铝内氧化试验方法制备了Al2O3/Cu 表面复合材料,研究了纯铜深层渗铝内氧化的金相组织特征及性能,结果表明: 与纯铜试样相比,深层渗铝内氧化试样的抗磨粒磨损性能和抗粘着磨损性能分别为纯铜试样的1.85倍和9.4倍,抗热疲劳性大幅度提高,经250次热循环后,内氧化试样质量损失率为纯铜试样的0.88%.这种特性使得纯铜深层渗铝内氧化Al2O3/Cu 复合材料在高温服役条件下更适合用作冶金设备用传热铜材料.     

Cu-Ti合金薄膜的微结构和力学性能

通过磁控共溅射方法制备了一系列不同Ti含量的Cu-Ti合金薄膜,采用EDS、XRD、TEM、AFM和纳米力学探针表征了薄膜的微结构和力学性能,研究了化合物对超过饱和固溶薄膜的强化作用。结果表明,由于溅射粒子的高分散性和薄膜生长的高非平衡性,Cu-Ti薄膜形成了超过饱和固溶体,晶格的剧烈畸变使Cu固溶体晶粒迅速细化。随Ti含量的增加,薄膜中产生高分散的细小Cu Tix化合物,并逐步形成Cu超过饱和固溶体纳米晶和细小化合物分布于非晶基体中的结构。与微结构的变化相应,薄膜的硬度随Ti含量的增加持续提高,并在含21.4%Ti(原子分数)时达到8.7GPa的最高值。高分散金属间化合物的存在是Cu-Ti合金薄膜在形成非晶结构后硬度得以继续提高的原因。     

Cu—Zn—Cr合金的时效特性

研究了不同时效工艺对Cu-Zn-Cr合金的力学性能、电学性能及其显微组织的影响。结果表明：固溶－冷变形后合金的时效过程由过饱和固溶体的析出过程和基体的再结晶两个过程控制；合金高强度主要来源于加工硬化和第二相铬粒子的析出强化，合金的高导电性则主要来源于贫化后成份接近于铜锌固溶体的基体。     

因瓦合金强化途径研究概况

简要介绍了固溶强化、形变强化、细晶强化和沉淀强化的强化机理.总结了高强度低热膨胀合金研究的国内外现状和达到的水平,对高强度低热膨胀合金将来的研究方向提出了看法.     

钎焊法制备硬质颗粒复合材料的耐磨性和磨损机理

为了提高硬质颗粒复合合金材料的耐磨性并揭示其与界面结合、微观组织及磨损机理之间的关系,本文设计并通过钎焊法,在普通铸钢件表面制得了厚度可达30mm的WC颗粒增强铜基合金覆层,测试分析了上述各种因素对此覆层耐磨性的影响.力学性能测试表明:该覆层与钢母体结合强固,且具有良好的综合性能.SEM观察和能谱分析说明:复合合金层组织由弥散强化铜基合金基体与WC颗粒相组成,且二者形成了强有力的反应性结合.磨料磨损试验证明:该复合合金在二体和三体磨损条件下均有较高的耐磨性,与低合金钢的切削和犁沟变形应变疲劳以及高铬铸铁的切削磨损机理不同,该复合合金与切削及脆性剥落两大磨损机理相对应.     

V85Ti10Y5和V85Ti10Cu5氢分离合金组织与性能研究

利用高真空非自耗电弧熔炼炉制备了V85Ti10Y5和V85Ti10Cu5氢分离合金。通过SEM、TEM、XRD、氢渗透实验、PCT吸氢实验、恒压缓冷实验,研究了Y、Cu元素的加入对合金氢渗透性能、氢溶解性能及抗氢脆性能的影响。结果表明:铸态V85Ti10Y5和V85Ti10Cu5合金组织均由V-基体和第二相组成,但前者第二相是弥散分布的富Y颗粒,而后者为既在晶内析出又沿晶界连续分布的铜钛金属间化合物。V85Ti10Y5合金中Y2O3的生成及V85Ti10Cu5合金中部分固溶Cu的斥氢作用和Cu2Ti形成使V中Ti的固溶量减少,进而降低合金中的氢浓度,减小氢固溶产生的内应力,提高抗氢脆性能。V85Ti10Y5和V85Ti10Cu5合金在缓冷过程中均未发生氢脆现象,表现出优异的抗氢脆性能,而且在673 K时的氢渗透率分别为0.139×10-6 mol H2 m-1 s-1 Pa0.5和0.174×10-6 mol H2 m-1 s-1 Pa0.5,是Pd77Ag23氢渗透率的5.5和6.9倍,与商用钯合金相比均展现出较高的渗透率。     

Surface alloying of Cu with Ti by double glow discharge process

The surface of pure copper alloyed with Ti using double glow discharge process was investigated. The morphology, structure and forming mechanism of the Cu-Ti alloying layer were analyzed. The microhardness and wear resistance of the Cu-Ti alloying layer were measured, and compared with those of pure copper. The results in-dicate that the surface of copper activated by Ar and Ti ions bombardment is favorable to absorption and diffusion of Ti element. In current experimental temperature, as the Ti content increases, the liquid phase occurs between the deposited layer and diffused layer, which makes the Ti ions and atoms easy to dissolve and the thickness of Cu-Ti al-loying layer increase rapidly. After cooling, the structure of the alloying layer is composed of CuTi, Cu4Ti and Cu(Ti) solid solution. The solid solution strengthening and precipitation strengthening effects of Ti result in high surface hardness and wear resistance.     

Microstructure and mechanical properties of the TiZrNbMoTa refractory high-entropy alloy produced by mechanical alloying and spark plasma sintering

The equiatomic refractory high entropy alloy (HEA) TiZrNbMoTa was investigated. The alloyed powders with face-centered cubic (FCC) structured solid solution phase were prepared by mechanical alloying (MA) and then sintered by spark plasma sintering (SPS) at 1300, 1400, 1500, and 1600 °C. The microstructure and mechanical properties of the bulk alloy were investigated. The body-centered cubic (BCC) structured solid solution phase and the ZrO₂ phase precipitated from the FCC structured solid solution phase during cool-down from sintering. The highest compression fracture strength (3759 MPa) and fracture strain (12.1%) were obtained in the refractory HEA sintered at 1400 °C. The grain boundary strengthening, precipitation strengthening, solid solution strengthening, transformation-induced plastic (TRIP) effect, and toughening effect of the ZrO₂ phase are the important factors for the high strength and ducitily of the refractory HEA prepared in this study.     

柱塞表面激光熔覆铁基涂层的强韧化机理

文中在柱塞表面激光熔覆制备高硬度铁基涂层,采用SEM,XRD,EPMA和TEM等手段研究熔覆层组织特征及耐磨性,阐述其强韧化机理.结果表明,激光熔覆铁基合金涂层成形良好,无裂纹及气孔等缺陷,熔覆层与基体呈冶金结合,组织由(Ni,Fe)固溶体、(Cr,Fe)₂₃C₆碳化物和少量孪晶马氏体组成.铁基熔覆层的强化机制主要有细晶强化、固溶强化、弥散强化以及马氏体强化;熔覆层内(Ni,Fe)固溶体及细晶强化的综合作用,保证了高硬度铁基涂层的韧性.铁基熔覆层显微硬度较45钢提高4倍,最大值H_HV0.2=850 GPa;熔覆层耐磨性明显高于45钢,45钢表面出现大面积疲劳剥落,铁基熔覆层磨损面平整,磨痕很浅且少,磨损机制为轻微的磨粒磨损.     

铬青铜和铜铬锆热处理前后的显微组织

采用高分辨的透射电子显微镜分析铬青铜和铜铬锆在固溶时效处理前后的显微组织。结果表明,铬青铜和铜铬锆合金在固溶时溶解于铜基体的强化相Cr在时效后弥散均匀分布在基体Cu上。铬与铜没有中间相或化合物形成,铜铬锆固溶时效处理后组织中的析出相要比铬青铜组织中的析出相尺寸小,铜铬锆晶界处偏聚的析出相尺寸也比铬青铜晶界处的析出相小,而且添加锆所构成的铜合金则有Cu5Zr相的析出。     

Microstructure and strengthening mechanisms of Mg-6Al-6Nd alloy

The microstructure and strengthening mechanisms of as-cast Mg-6Al-6Nd alloy were studied. The results show that the addition of 6 wt.% Nd into Mg-6Al alloy leads to the precipitation of Al11Nd3 and Al2Nd phases and decrease in the content of Al solid soluted in Mg-Al matrix. The volume fractions of Al11Nd3 and Al2Nd phases are 3.64% and 0.34%, respectively. Compared with Mg-6Al alloy, the ultimate strength, yielding strength, and elongation of Mg-6Al-6Nd alloy at room temperature and 175°C are enhanced in some degrees. The strengthening mechanisms of Mg-6Al-6Nd alloy are mainly composed of solid solution strengthening of Al solid soluted in Mg-Al matrix and grain refinement strengthening, dispersion strengthening, and composite strengthening brought by the precipitation of Al11Nd3 phase. The composite strengthening includes the load transfer from the matrix to Al11Nd3 phase and the enhancement of dislocation density due to the geometrical mismatch and thermal mismatch between the matrix and Al11Nd3 phase.