Cu-Zr基块体非晶合金的研究进展

针对Cu基非晶合金这一具有广阔应用前景的新型非晶合金,从合金体系、性能及应用等方面对其国内外研究现状和进展进行了综述。重点分析了Cu基非晶合金体系中各合金元素的作用、合金的力学性能和耐腐蚀性能。简要介绍了表征合金玻璃形成能力(GFA)的参数和判据,特别是近几年新提出来的参数和判据。最后对Cu基块体非晶合金目前存在的问题及其应用前景进行了概述。     

Cu基非晶合金的最新研究进展

Cu基非晶合金是一种高性能材料,本文从Cu基非晶合金体系、形成能力、影响因素、力学性能以及Cu基复合材料几个方面对Cu基非晶合金进展进行了综述,提出了Cu基非晶合金的发展方向,同时展望了Cu基块状非晶合金的工程应用前景。     

块体非晶(玻璃态)合金功能材料

Fe Co Ga P C B铁基非晶合金的软磁性能〔1〕　近年来发现了一系列铁基的多元非晶合金Fe (Al,Ga) (P ,C ,B ,Ge ,Si)和Fe (Nb ,Mo ,Zr ,W ) B等 ,它们具有很大的过冷液相区 (5 8～ 88K)并能用铜模铸造法生产 2～ 6mm直径的非晶态棒材。但这些大块非晶合金含Fe量都少于 73% (原子 ) ,以致饱和磁化强度不高 (<1 1T)。最近开发了含Fe更高的高饱和磁化强度 (1 3T左右 )块体非晶合金Fe75Ga5P12C4 B4 。为了进一步改善这一合金的性能 ,研究了加Co的效果。研究用的合金是由纯铁、钴、镓和预制合金铁碳、铁磷块、纯硼晶体原料配料在…     

Zr-Ti-Cu-Ni-Be-Fe块体非晶合金及非晶基纳米复合材料的形成及其性能

采用水淬法制备出了块状、高强度Ｚｒ－Ｔｉ－Ｃｕ－Ｎｉ－Ｂｅ－Ｆｅ非晶合金,研究了铁原子组元对Ｚｒ－Ｔｉ－Ｃｕ－Ｎｉ－Ｂｅ－Ｆｅ块体非晶形成能力硬度、磁化率及其热稳定性的影响。结果表明,当Ｆｅ含量超过１０％（原子分数）时,在合适的冷却速率下可以区得含有钠米晶凿的非晶基复合材料。     

Cu-Zr-Nb系铜基块体非晶合金的形成

Cu8Zr3和Cu10Zr7相中存在Cu8Zr5和Cu6Zr5团簇结构,它们与Cu-Zr系的两个深共晶点Cu61.8Zr38.2和Cu56Zr44对应. Cu64Zr36是Cu-Zr二元系具有最大玻璃形成能力的成分点.依据形成块体非晶的＂变电子浓度线判据＂,以Cu64Zr36,Cu61.8Zr38.2和Cu56Zr44 3个二元成分为出发点,以Nb元素为第三组元,建立变电子浓度线（Cu64Zr36）100-xNbx,（Cu61.8Zr38.2）100-xNbx和（Cu56Zr44）100-xNbx.采用分步熔炼法,由铜模吸铸法制备直径为3 mm的合金棒.块体非晶的玻璃形成区及玻璃形成能力由XRD和热分析确定.结果表明,添加少量Nb（原子分数,x≤3）可以显著提高Cu-Zr二元系的玻璃形成能力.具有最大Tg/Ti值（0.626）的成分Cu60.3Zr37.2Nb2.5位于具有Cu8Zr5团簇和最深共晶点的Cu61.8Zr38.2向第三组元Nb的连线上.结合Cu-Zr二元体系的团簇结构讨论了Cu-Zr-Nb系块体非晶的形成.     

Cu模吸铸法制备Cu-基块体非晶合金

采用磁悬浮熔炼和Cu模吸铸工艺成功制备了圆棒Cu50Zr42Al8块体非晶合金，试样表面平滑且具有典型的金属光泽。试验制备的圆棒Cu50Zr42Al8块体非晶合金的直径尺寸小于Ф5mm，该成分的块体非晶合金具有较强的非晶形成能力，其玻璃转变温度Tg=723K，晶化温度t=773K，过冷度△T=50K，约化玻璃转变温度Trg=0.753。     

Cu基二元块体非晶合金形成能力的热力学分析

研究了Cu基二元块体非晶合金的形成能力,解释了多元合金的非晶形成能力。通过比较已有的二元铜基块体非晶合金的试验数据发现,在内能差相差不大的情况下,混合熵差对于非晶形成能力有着重要的影响。     

Zr-Cu-Ni-Ta-Al块体非晶合金复合材料的合成及力学性能

采用电弧熔炼铜模铸造法制备了Ta晶体相增强的Zr基非晶合金复合材料。利用差示扫描量热仪（DSC），X射线衍（XRD）射仪，扫描电子显微镜（SEM）等手段研究了Ta加入对（Zr0.65Cu0．175Ni0.175）90-xTaxAl10（x=0，4，6，8，10）（原子百分比）非晶复合材料非晶形成能力及力学性能的影响。结果表明，Ta的加入改变了合金的晶化行为，随着Ta含量的增加，合金的DSC曲线由单一晶化峰转变为多个晶化峰。加入10％Ta的块体非晶合金复合材料的基体固溶约4％的Ta。复合材料的塑性应变量达到3．2％，同时最大应力达到1855MPa，明显高于不含Ta合金。块状非晶合金复合材料中Ta晶体相的存在，阻止单一剪切带的扩展，诱发更多剪切带形成，从而提高了材料的抗压强度和塑性。     

新型铜基块体非晶合金Cu55-xZr37Ti8Inx的制备及性能

利用铜模吸铸法合成Cu—ZrTi—In非晶棒。块体非晶合金Cu50Zr37Ti8In5的△瓦值最大,为66K。从原子尺寸大小和热力学角度分析在铜基非晶合金中添加适量In元素后能够提高其非晶形成能力的原因。在所测的块体非晶合金Cu55．Zr37Ti8Inx（x≤〈5）,Cu52Zr37Ti8In3表现出最高的抗压强度（1981MPa）和最佳的塑性,其在压缩断裂前的总塑性变形量约为1．2％。     

高应变速率下钨丝增强锆基块体非晶合金复合材料的变形行为

利用压力浸渗制备出钨丝增强Zr_(41．25)Ti_(13．75)Ni_(10)CU_(12．5)Be_(22．5)块体非晶合金复合材料,采用应变速率为1×10~(-4) s~(-1)的准静态压缩实验及应变速率为2×10~3s~(-1)的动态压缩实验的方法,研究了在动载荷作用下该复合材料的力学性能．结果表明,准静态压缩时,复合材料的强度约为1980 MPa,与单一块体非晶合金相比并无显著提高．而塑性提高约5倍,达到11．5%;动态压缩时,复合材料的最大抗压强度升至约2648 MPa,塑性则在1．8%—7．5%之间,复合材料的应变速率敏感指数为0．022．在准静态压缩下,复合材料的抗压强度受到残余热应力及钨丝失稳弯曲极限压应力的影响;在动态压缩下,除了热应力的影响外,还受到钨丝剪切断裂以及复合材料正弦型弯曲行为的影响．后两者使复合材料的抗压强度在动态加载条件下升高．     

固结参数对热压成型铜基块体非晶合金力学性能的影响

采用雾化法制备Cu50Zr40Ti10非晶合金粉末,在大气环境下将其热压成型为块体非晶合金,并基于L9（34）正交实验对热压成型条件进行优化。固结成型的Cu50Zr40Ti10块体非晶合金的抗压强度和应变极限值分别达到1090.4MPa和11.9%。固结压力显著影响块体非晶合金的应变极限和抗压强度,但是固结温度的影响不显著。初始成形力对块体非晶合金的抗压强度的影响不显著而对应变极限的影响很显著。Cu50Zr40Ti10非晶合金粉末的最优热压成型工艺条件为：首先在150MPa压力下进行预成型,然后在380°C和450MPa条件下进行热压。     

Fabrication of carbon nanotube reinforced AZ91D composite with superior mechanical properties

AZ91D alloy composites with 1.0% CNTs have been fabricated by a method combined ball milling with stirring casting. The composite was investigated using optical microscopy(OM), X-ray diffraction(XRD), Fourier transform infrared spectroscope (FT-IR), scanning electron microscope (SEM), transmission electron microscope (TEM) and room temperature (RT) tensile test. The results show that CNTs were homogeneously distributed in the matrix and maintained integrated structure. The yield strength and ductility of AZ91D/CNTs composite were improved by 47.2% and 112.2%, respectively, when compared with the AZ91 alloy. The uniform distribution of CNTs and the strong interfacial bonds between CNT and the matrix are dominated to the simultaneous improvement of yield strength and ductility of the composite. In addition, the grain refinement as well as the finer β phase (Mg₁₇Al₁₂) with homogenous distribution in the matrix can also slightly assist to the enhancement of the mechanical properties of the composite.     

Preparation and properties of Cu matrix composite reinforced by carbon nanotubes

Cu matrix composites reinforced by carbon nanotubes(CNTs) were prepared. The effect of carbon nanotubes on mechanical and tribological properties of the Cu matrix composites were investigated. The chemical method for coating CNTs was reported. The morphology of the fracture surfaces and worn surface were examined by SEM.The results show that Cu/coated-CNTs composites have higher hardness, much better wear resistance and antifriction properties than those of the reference Cu alloy (Cu-10Sn) and Cu/uncoated-CNTs composite sintered under the same conditions. The optimal mechanical properties of the composites occurred at 2. 25%(mass fraction) of CNTs. The excellent wear resistance and anti-friction properties are attributed to the fiber strengthening effect of CNTs and the effect of the spherical wear debris containing carbon nanotubes on the tribo-surface.     

Fe基非晶合金增强1060铝基多层复合材料的组织与性能

采用累积叠轧焊+中间退火法复合轧制1060Al/Fe基非晶多层铝合金复合板材。利用光学显微镜、扫描电镜、X-衍射分析仪以及拉伸试验机分析Al基复合材料的微观组织结构变化、断口形貌、物相组成以及力学性能。结果表明:Fe基非晶复合材料的增强体在300 ℃中间退火过程中发生部分晶化,在累积变形轧制过程中发生破碎,并随着变形道次的增加,破碎程度随之增大;复合板前6道次的累积轧制变形出现了明显的加工软化现象,并且随着变形道次的增加,其加工软化的效果愈明显;随着累积轧制变形道次增加,Al基复合材料的力学性能发生了明显的变化,第2道次轧制变形后屈服强度与抗拉强度达到了最大值为140 MPa和156 MPa,伸长率为5.53%,达到最佳综合性能。     

大块非晶材料的性能及其应用

介绍大块非晶合金的性能及其应用,简单介绍了熔体水淬法、爆炸焊接法等制备大块非晶合金的技术。     

Fabrication of carbon nanotubes reinforced AZ91D composites by ultrasonic processing

Magnesium matrix nanocomposite reinforced with carbon nanotubes （CNTs/AZ91D） was fabricated by mechanical stirring and high intensity ultrasonic dispersion processing. The microstructures and mechanical properties of the nanocomposite were investigated. The results show that CNTs are well dispersed in the matrix and combined with the matrix very well. As compared with AZ91D magnesium alloy matrix, the tensile strength, yield strength and elongation of the 1.5%CNTs/AZ91D nanocomposite are improved by 22%, 21% and 42% respectively in permanent mold casting. The strength and ductility of the nanocomposite are improved simultaneously. The tensile fracture analysis shows that the damage mechanism of nanocomposite is still brittle fracture. But the CNTs can prevent the local crack propagation to some extent.     

预退火时间对Cu50Zr42Al8玻璃转变及晶化行为的影响

采用示差扫描量热(DSC)分析方法,研究了预退火处理对Cu50Zr42Al8块状非晶合金的玻璃转变温度Tg、起始晶化温度Tx、以及玻璃转变过程中的比热容变化的影响.结果表明:Cu50Zr42Al8块状非晶合金在2～64h的预退火处理下,其焓弛豫峰的变化趋势与玻璃转变过程中的比热变化△Cp,g和玻璃转变温度Tg的变化一致,都是随预退火时间的增加先增加后减少.而其起始晶化温度Tx随着预退火时间的延长而减小.基于有序原子团簇引起微观结构变化,利用结构弛豫理论讨论了预退火时间影响玻璃转变和晶化过程的机理.     

无定型碳包覆的TiO2纳米管阵列的制备及表征

本文通过将水热碳化法和阳极氧化法相结合制备了具有良好电化学性能的无定型碳包覆的混晶型TiO2纳米环阵列(C@TNTs)。利用扫描电镜(SEM)、拉曼光谱(Raman)、X射线衍射(XRD)、透射电镜(TEM)和X射线光电子能谱(XPS)及电化学测试等表征方法对未修饰的TNTs试样和在550 °C、650 °C和750 °C退火温度下得到无定形碳修饰的C@TNTs分别进行了表征分析。结果表明：水热碳化法可以将厚度约为3.4~6.5 nm无定型碳层均匀地包覆在TiO2纳米管阵列上,但却不会影响其形貌和结构;其中C@TNTs-550、C@TNTs-650和C@TNTs-750的放电比容量分别为2.83 mF·cm-2、6.52 mF·cm-2和1.48 mF·cm-2,相较于未修饰前的TNTs分别提升了27、62和14倍;此外,在TiO2纳米管阵列中引入一定量的金红石相有利于其电化学性能的提升。     

Carbon nanotube reinforced aluminum composite fabricated by semi-solid powder processing

Semi-solid powder processing (SPP) is a promising technology that combines the benefits of semi-solid forming and powder metallurgy. In this study, carbon nanotube (CNT) reinforced aluminum alloy 6061 (Al6061) composite was synthesized by SPP for the first time. Mechanical alloying was used to disperse the CNTs in the matrix phase. The effects of the processing temperature (600 °C, 620 °C and 640 °C) on the microstructure, hardness, fracture surface and composition of the Al6061-CNT composite were investigated. Overall, the Al6061-CNT composite showed full densification above 99% with 100 MPa of pre-compaction and 50 MPa of pressure during consolidation in the semi-solid regime. Microstructure and the fracture surface analyses showed that the CNTs were uniformly dispersed throughout the Al6061 matrix. Higher density composite was obtained at higher liquid content, although the highest composite hardness was achieved when processed at 620 °C. It was speculated that the formation of carbides at higher temperatures affected the interface bonding between the matrix and CNT. The study showed feasibility of manufacturing CNT reinforced metal composites by SPP.     

Nanoscale Ni-B amorphous alloy catalyst supported on carbon nanotubes

Heat treatment of carbon nanotubes （CNTs） was carried out under ammonia atmosphere and then CNTs were modified by Triton x-100 （CNTs-T）. Ni-B amorphous alloy catalysts supported on CNTs and CNTs-T were prepared by impregnation-chemical reduction method. The catalysts were characterized by TEM, ICP, XRD, BET and CO chemisorption, and studied in the acetylene selective hydrogenation. The results show that homogeneous Ni-B amorphous particles with mean size about 10 nm are successfully prepared on CNTs-T. Compared with Ni-B/CNTs, nickel loading of Ni-B/CNTs-T is increased by about 14.6%. Furthermore, the activity and selectivity of Ni-B/CNTs-T are much higher than those of Ni-B/CNTs in the acetylene selective hydrogenation under comparative condition.