熔盐电解制备低成本Ti12LC钛合金的研究

利用覆盖渣技术在非真空条件下成功制备出了直径为3 mm的Zr55Ni5Al10Cu30块体非晶合金.采用差示扫描量热法(DSC),将Johnson-Mehl-Avrami理论拓展应用于非晶合金的非等温晶化过程研究.结果表明,Zr55Ni5Al10Cu30块体非晶合金的连续升温晶化过程Avrami指数及形核率随升温速率的升高而呈下降趋势,同时随晶化过程进行呈先增加后减小的规律.Avrami指数最大值出现在晶化体积分数0.3～0.4之间,在低升温速率下Zr55Ni5Al10Cu30块体非晶合金部分晶化过程出现三维形核界面控制长大的形式.     

Zr-Ti-Cu-Ni-Be大块非晶合金等温晶化过程相分离研究

利用差示扫描量热法(DSC)和透射电镜(TEM)对Zr41.2Ti13.8Cu12.5Ni10Be22.5(at％)大块非晶合金的等温晶化过程和析出相进行了研究。结果表明，大块非晶合金在等温晶化过程中表现出多阶段相析出行为，并且在不同的晶化阶段，析出相也有所不同。在第1个晶化阶段，析出相主要是体心四方(b.c．t)结构的Zr2Cu相；而在晶化的第2个阶段，晶化相主要为简单六方结构的ZrBe2相。从一定程度上证实了Zr41.2Ti13.8Cu12.5Ni10Be22.5大块非晶合金在发生晶化时会形成富Zr区和富Be区，即有相分离的趋势。XRD测试的结果也证实了非晶合金在发生完全晶化时，主要的晶化产物为Zr2Cu和ZrBe2相。     

Zr55Al10Ni5Cu30块状非晶合金靠近玻璃转变点的等温纳米晶化

研究了Zr55Al10Ni5Cu30块状非晶合金靠近玻璃转变点等温晶化过程。结果表明：420℃退火5h,出现了尺寸为20nm左右的晶相,同时,非晶基体也出现了尺寸为1－2nm分布均匀的团簇状结构;退火10h,析出的晶相尺寸为20－50nm,所占的体积分数为40％;退火20h之后,非晶相完全转变为亚稳相,析出的晶相尺寸为50nm左右,并没有出现明显的长大现象。退火得到的晶相为Cu10Zr7,Zr2Ni及一些未能标定的相,这些相在420℃具有相对的稳定性,没有问题稳定相转变。退火后,残余非晶相的热稳定性降低。等温退火过程经历了从非晶相→团簇状结构→亚稳相的转变过程。     

Thermal stability of Zr_(55)Al_(10)Ni_5Cu_(30)bulk amorphous alloy during continuous heating and isothermal annealing

1　INTRODUCTIONBulkamorphousalloyspossessalongrangedis orderbutshortrangeorderstructure ,whichresem blesthestructureofliquid .Andthereisasupercooledliquidregionbeforecrystallizationofabulkamor phousalloy .Thisuniquestructureresultsinexcellentpropertiessuchashightensilestrength ,highhard ness,highimpactfractureenergy ,highelasticener gy ,highcorrosionresistance ,highviscousflowabilityandgoodsoftmagnetism[13] .Thesynthesisofmetallicglassesinabulkform (withthickness >1mm )wassuccessfullyachi…     

HRTEM study of crystallization of Zr–Cu–Ni metallic glass

Employing differential scanning calorimetry (DSC) and high-resolution transmission electron microscopy (HRTEM), the micromechanism for crystallization of Zr₇₀Cu₂₀Ni₁₀ metallic glass under isothermal annealing conditions has been investigated. It is found that the relationship between the annealing temperature and the peak position, incubation time and ending time in the isothermal annealing DSC traces of Zr₇₀Cu₂₀Ni₁₀ metallic glass obeys a first-order exponential function. However, the time–temperature transformation curves of Zr₇₀Cu₂₀Ni₁₀ metallic glass at different crystallized volume fractions can be well fitted by a second-order exponential function. It is observed that at the initial crystallization stage some ordered atomic clusters precipitate first, acting as nucleation sites and facilitating the subsequent crystallization process, and the crystal growth process mainly proceeds through the atomic depositing on the previously formed crystals. This behavior confirms that the new micromechanism for crystallization of amorphous alloys proposed by Lu and Wang can also be applied to the new series of zirconium based amorphous alloys.     

Crystallization kinetics of Zr41Ti14Cu12.5Ni10Be22.5 bulk metallic glass

1　ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｍｅｔａｌｌｉｃｇｌａｓｓｅｓｈａｖｅｔｈｅｓｔｒｕｃｔｕｒｅｏｆｌｏｎｇ ｒａｎｇｅｒａｎｄｏｍａｎｄｓｈｏｒｔ ｒａｎｇｅｏｒｄｅｒ .Ｃｏｍｐａｒｅｄｗｉｔｈｃｒｙｓｔａｌｌｉｎｅａｌｌｏｙ ,ｔｈｅｙｈａｖｅａｌｏｔｏｆ     

高温变形对(Cu50Zr50)92Al8等温晶化行为及其力学性能的影响

研究了(Cu50Zr50)92Al8非晶合金在过冷液相区中,经过牛顿流变和非牛顿流变后的等温晶化行为及其对该合金力学性能的影响。结果表明,牛顿型流变对(Cu50Zr50)92Al8非晶合金的结构没有明显的影响;而非牛顿流变对该非晶的显微结构及其等温晶化行为有显著影响:非牛顿流变促进了(Cu50Zr50)92Al8非晶合金的晶化,其主要晶化相为体心立方结构的CuZr相(B2相)和CuZr马氏体相;经非牛顿流变及真空热处理试样,在室温压缩过程中,应力诱发了部分B2相的马氏体相变,从而使其在室温下表现出超弹性,当预塑性应变量为8%时,其总可回复应变为5%左右。     

电脉冲孕育处理对Zr基块体非晶热稳定性及退火晶化的影响

通过先对Zr55Ni5Al10Cu30合金熔体施加脉冲电流处理,再利用非真空吸铸法制备出Zr55Ni5Al10Cu30块体非晶合金的方式,研究了电脉冲孕育处理对非晶热稳定性及退火晶化的影响。差分扫描量热(DSC)及X射线衍射(XRD)分析结果表明:经电脉冲孕育处理后Zr55Ni5Al10Cu30块体非晶合金的玻璃转变温度上升,晶化温度降低,过冷液相区变窄,同时玻璃转变激活能和晶化激活能有所减少。电脉冲孕育处理没有改变Zr55Ni5Al10Cu30块体非晶合金退火晶化相演变过程,但提高了非晶退火晶化率。电脉冲孕育处理对Zr55Ni5Al10Cu30块体非晶合金的晶化起到了促进作用。     

Nb添加对Cu-Zr非晶合金等温晶化动力学的影响

采用铜模吸铸法制备了Cu50.3Zr49.7Nbx(x=0,2)块体非晶合金.利用示差扫描量热分析(DSC)研究了2at％Nb的添加对Cu-Zr非晶合金在过冷液相区等温晶化行为的影响.结果显示Cu基合金的等温晶化动力学符合JMA方程的定量描述.含微量Nb的合金具有更长的晶化孕育时间、更宽的反应放热峰以及更低晶化速率常数k和Avrami指数n,与此同时局域Avrami指数n随晶化体积分数的变化和Nb的添加而改变.这表明微量Nb添加在抑制合金形核,提高其热稳定性的同时,也改变了Cu基合金的等温晶化过程.     

Crystallization kinetic characteristics of oxygen-induced/-phase and Zr2Cu phase in Zr65Cu27.5A17.5 glassy alloy

Based on the construction of TTT diagrams by isothermal DSC measurements, the thermal stabilities of Zr65Cu27.5A17.5 glassy alloys containing 0.68% and 0.06% [O] （molar fraction） were compared. The changing tendencies of the thermal stabilities reflected in the TTT-diagrams were validated by XRD analyses and TEM observations. The crystallization kinetic characteristics of oxygen-induced I-phase and Zr2Cu phase in Zr65Cu27.sm17.5 glassy alloy were discussed. It is found that oxygen promotes the precipitation of I-phase and retards the formation of Zr2Cu phase. If the pre-crystallization event for oxygen-induced I-phase is permitted and the main-crystallization event for Zr2Cu phase is taken as the thermal stability criterion, the alloy with higher oxygen content has longer onset time for crystallization within a rather large supercooling temperature range. The possibility for the preparation of Zr65Cu27.sm17.5 glassy alloy-based composite containing oxygen-induced I-phase was also forecasted.     

Crystallization kinetic characteristics of oxygen-induced I-phase and Zr2Cu phase in Zr65Cu27.5Al7.5 glassy alloy

Based on the construction of TTT diagrams by isothermal DSC measurements,the thermal stabilities of Zr65Cu27.5Al7.5 glassy alloys containing 0.68% and 0.06% [O] (molar fraction) were compared.The changing tendencies of the thermal stabilities reflected in the TTT-diagrams were validated by XRD analyses and TEM observations.The crystallization kinetic characteristics of oxygen-induced I-phase and Zr2Cu phase in Zr65Cu27.5Al7.5 glassy alloy were discussed.It is found that oxygen promotes the precipitation of I-phase and retards the formation of Zr2Cu phase.If the pre-crystallization event for oxygen-induced I-phase is permitted and the main-crystallization event for Zr2Cu phase is taken as the thermal stability criterion,the alloy with higher oxygen content has longer onset time for crystallization within a rather large supercooling temperature range.The possibility for the preparation of Zr65Cu27.5Al7.5 glassy alloy-based composite containing oxygen-induced I-phase was also forecasted.     

反复熔炼对Zr基大块非晶合金玻璃形成能力的影响

研究了反复熔炼对Zr60Al15Ni25和Zr65Al7.5Ni10Cu17.5合金的玻璃形成能力的影响。DSC分析表明，随着熔炼次数的增多，Zr60Al15Ni25非晶合金的玻璃转变温度和晶化开始温度都提高，而Zr60Al7.5Ni10Cu17.5非晶合金的特征温度基本没有发生变化。Zr60Al15Ni25合金的熔化焓由于反复熔炼而降低，在热力学上有利于非晶相的形成。根据反复熔炼对铸锭凝固组织进而对合金熔体中的短程序的影响，讨论了玻璃形成能力的变化及原子间的结合力对短程序尺寸的影响，分析了2种合金对反复熔炼处理的敏感性的不同。     

Microstructure and thermal expansion of copper-based amorphous alloys during structural relaxation

(Cu43Zr48Al9)98Y2 amorphous alloy bar was prepared by the arc melting copper mold absorption casting method,and then,the amorphous alloy was annealed at different temperatures for different times.The influence of heating rate on thermal expansion and thermal stability was studied by thermomechanical analysis(TMA),and the microstructure evolution of the amorphous alloy during structural relaxation and crystallization was studied by XRD and TEM.Results show that the structural evolution behavior of the(Cu43Zr48Al9)98Y2 amorphous alloy can be divided into five different stages(structural relaxation preparation stage,structural relaxation stage,first crystallization stage,second crystallization stage,and grain growth stage).When the heating rate is 20 K/min,the amorphous alloy has the smallest thermal expansion coefficient and the best thermal stability.The width of the supercooled liquid region is 66.42 K.Samples with different relaxation states were prepared by annealing at the heating rate of 20 K/min.The structural evolution of amorphous alloys with different relaxation states is as follows:amorphous→CuZr2+AlCu2Zr7→CuZr2+AlCu2Zr7+CuZr(B2)+CuZr(M)+Cu10Zr7→CuZr2+AlCu2Zr7+CuZr(B2)+CuZr(M).After annealing at 706 K and 726 K(in the supercooled liquid region)for 1.5 h,the amorphous-nanocrystalline composites were obtained.When the annealing temperature is 706 K,the crystallization process of the sample is as follows:amorphous→Cu10Zr7→Cu10Zr7+CuZr,and for the sample at 726 K,it is as follows:amorphous→CuZr2+AlCu2Zr7+Cu10Zr7→Cu10Zr7+CuZr2→CuZr2+CuZr(B2)+Cu10Zr7.     

Zr52.5CU17.9Ni14.6Al10Ti5块体非晶退火后的力学性能

观察亲测试了Ｚｒ５２．５Ｃｕ１７．９Ｎｉ１４．６Ａｌ１０Ｔｉ５块体非晶在不同退火条件下的显微组织与力学性能,等温退火后可以得到尺寸约为３０－６０ｎｍ金属间化合物相用分布在非晶基体上的混合结构,研究表明：Ｐ块体非晶的压缩屈服强度为１．６６ＧＰａ,断裂强度为１．７８ＧＰａ,塑性约为０．５％,等温退火后,材料强度随着析出纳米相的体积分数（Ｖ）的培加发生明显的变化,Ｖ＝１８％时为１．９１ＧＰａ,Ｖ＝４７＾     

放电等离子烧结-非晶晶化法合成Ti7oNb7.8Cu8.4Ni7.2Al6.6复合材料

采用机械合金化制备不含和含2%(体积分数)B4C的钛基非晶合金粉末,随后采用放电等离子烧结-非晶晶化法合成不含／含(TiB+TiC)的Ti7oNb7.8Cu8.4Ni7.2Al6.6超细晶／细晶钛基复合材料;运用X射线衍射分析(XRD)、差示扫描量热分析(DSC)、扫描电子显微镜(SEM)和万能材料试验机等对制备的钛基非晶粉末和超细晶／细晶钛基复合材料进行表征.结果表明高能球磨80h的钛基粉末中主要为非晶相,B4C颗粒的加入对钛基粉末的玻璃转变温度、晶化温度和晶化焓有显著的影响.另外,不含／含(TiB+TiC)的复合材料的显微硬度分别为5.47和5.33GPa;以50K/min升温到1223K并保温10min获得的Ti70Nb7.8Cu8.4Ni7.2Al6.6块体试样的断裂强度和断裂应变分别为2098MPa和11.5%.     

Crystallization of amorphous Zr70Cu30—xNix alloys

X－ray diffraction (XRD)and differential scanning calorimetry(DSC) were employed to investigate the influence of Ni content on the crystallization of amorphous Zr70Cu30-xNix(atom fration in%) alloys,Experimental results show that with the Ni content increasing the activation energies for crystallization of amorphous Zr70Cu30-xNix alloys increase correspondingly,indicating that the thermal stability is greatly improved.All the DSC traces of amorphous Zr70Cu30-xNix alloys exhibit two exothermic peaks,suggesting that the crystallization process via a double-stage ticles,while the second one corresponds to the precipitaion of nano-scale Zr2Ni phase and crystallization of residual amporphous phase,The mechanism on the crystallization of amorphous Zr70Cu30-xNix alloys was discussed.     

Cu64Zr36非晶合金的晶化动力学

利用单辊急冷法制备了CH64Zr36非晶合金，使用盐浴等温退火并用DSC和XRD研究了其晶化过程、玻璃转变和晶化动力学。结果表明：CH64Zr36非晶合金的晶化过程为：非晶一非晶＋Cu10Zr7→Cu10Zr7＋CuZr2。该合金的玻璃转变和晶化激活能分别为433．7kJ／mol和603kJ／mol。     

添加剂对低压烧结Zr50Al15Ni10Cu25非晶态粉末力学性能的影响

以商业纯元素粉末为原料,用机械合金化方法在低真空条件下合成了以非晶态为主的Zr50Al15Ni10Cu25粉末。研究了一定量的外界添加剂C、Si3N4和SiC对体系热稳定性和晶化行为的影响。混合粉末用手工预压成形,然后在氩气氛下进行低压烧结。利用X射线衍射（XRD）、扫描电镜（SEM）、差热分析（DSC）和电子拉伸实验机对粉末样和块状样进行了测试。结果表明,合适的外界添加剂可以提高体系的析晶活化能,增强体系的热稳定性。适量的Si3N4能促进Zr50Al15Ni10Cu25非晶粉末的低压烧结性能,即有助于提高样品的烧结致密度和样品的抗弯强度。     

Amorphous in a Zr-IQC-DQC pseudo-ternary alloy system

A pseudo-ternary alloy system was constructed by combining an icosahedral quasicrystal (IQC), a decagonal quasicrystal(DQC), and Zr into one alloy system. Different proportions of Zr were added to pseudo-binary alloy IQC80DQC20 (mass fraction in %). Structural evolution in these alloys was discussed. An amorphous alloy composition was found in this system and a melt-spinning amorphous alloy was produced in this composition. Through DSC analysis, the amorphous alloy exhibits high glass forming ability comparable to that of the Inoue Zr65Al75Cu17.5Ni10 amorphous alloy.     

Zr57Nb5Cul5．4Nil2．6Al10大块非晶合金的晶化动力学及显微硬度

采用铜模铸造法制备直径10mm的圆柱状Zr57Nb5Cu15.4Ni12.6Al10大块非晶合金，并用X射线衍射(XRD)证明其为完全非晶态。应用示差扫描量热(DSC)分析方法测定该合金的玻璃转变的热学参量并分析其晶化过程。利用Kissinger法和Ozawa法计算了大块非晶合金表观晶化激活能。同时研究了退火温度对非晶合金显微硬度的影响。