合金相团簇规律及其在Zr-Al-Ni非晶体系中的应用

研究多个典型非晶形成体系合金相结构中的团簇规律,指出在合金相结构中团簇之间以不同方式共享原子的事实。共享后的有效团簇到合金相的连接方式有两种,一种是共享后的团簇成分就是相成分,无须连接原子,另一种是共享后的团簇加上连接原子才能构成空间相结构(这类相称之为团簇相)。这种方法使得对合金相的结构有了一个全新的理解。在典型的非晶形成体系Zr-Al-Ni中,团簇相有3个:AlNiZr-Fe2P结构,Al2NiZr6-InMg2结构和Al5Ni3Zr2-Mn23Th6结构。通过此项工作还提出了基于合金相结构来确定与非晶形成相关的团簇的方法,即与非晶相关的团簇一般为团簇相里出来的孤立团簇,这一结论在Zr-Al-Ni体系中得到了很好的验证。     

非晶合金的晶化动力学与初生相的内在联系

通过差示扫描量热法(DSC)研究了Zr60Al15Ni25非晶合金的晶化动力学。X射线衍射(XRD)和能谱(EDS)分析结果表明:Zr60Al15Ni25非晶合金晶化过程中的初生相为复杂三元化合物Al2NiZr6和AlNi4Zr5。非晶合金的有效晶化激活能反映了晶化初生相与非晶相间的结构差异,二者结构差异越大,有效晶化激活能就越高,Zr60Al15Ni25非晶合金的有效晶化激活能高达345 kJ/mol;当合金高温熔体快冷过程中的初生相与非晶合金的晶化初生相一致时,晶化动力学参数能够实际反映合金的玻璃形成能力,相反则不能。     

Fe79Zr9B12和Fe76Zr9B15合金的晶化行为和磁性能

采用单辊快淬法制备Fe79Zr9B12和Fe76Zr9B15非晶合金薄带,并对两合金进行不同温度下热处理。利用差热分析仪(DTA)、X射线衍射仪(XRD)和振动样品磁强计(VSM)研究Fe79Zr9B12合金和Fe76Zr9B15合金的晶化行为和磁性能。结果表明,Fe79Zr9B12合金和Fe76Zr9B15合金的晶化激活能分别为404.42 kJ/mol和370.75 kJ/mol。晶化初期,有α-Mn型相和α-Fe相从Fe79Zr9B12非晶合金基体中析出,Fe23B6型相和α-Fe相从Fe76Zr9B15非晶合金基体中析出。α-Mn型相和Fe23B6型相均为亚稳相,进一步高温热处理后,α-Mn型相转变为α-Fe相,Fe23B6型相转变为α-Fe相、Fe2B相和Fe3B相。Fe79Zr9B12合金的矫顽力(Hc)在600℃退火后突然增大,继续高温退火,Hc下降;Fe76Zr9B15合金的Hc随着退火温度的升高持续增大。两种合金矫顽力随退火温度的变化与退火后合金的微观结构密切相关。     

Crystallization process and shape memory properties of Ti–Ni–Zr thin films

The crystallization process of as-deposited Ti–Ni–(10.8–29.5)Zr amorphous thin films was investigated. The Ti–Ni–Zr as-deposited films with a low Zr content exhibited a single exothermic peak due to the crystallization of (Ti,Zr)Ni with a B2 structure. In contrast, a two-step crystallization process was observed in the Ti–Ni–Zr thin films with a high Zr content. Shape memory behavior of Ti–Ni–Zr thin films heat treated at 873–1073 K was investigated by thermal cycling tests under various stresses. The martensitic transformation start temperature increased with increasing Zr content until reaching the maximum value, then decreased with further increasing Zr content. The inverse dependence of transformation temperature on Zr content in the thin films with a high Zr content is due to the formation of a NiZr phase during the crystallization heat treatment. The formation of the NiZr phase increased the critical stress for slip but decreased the recovery strain.     

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。     

Determination of Isothermal Section of Fe-Ni-Zr Ternary System at 1198K

The isothermal section of Fe-Ni-Zr ternary system at 1198K was experimentally determined using diffusion triple technique together with scanning electron microscopy (SEM) and electron probe microanalysis (EPMA). The results indicate that there are seven binary intermetallic phases, Fe2Zr, FeZr2, NiZr2, NiZr, Ni10Zr7, Ni7Zr2, and Ni5Zr, found in the ternary system, the binary compounds NiZr2 and FeZr2 show a homogeneity range and form a continuous solid solution, namely (Fe, Ni)Zr2. Five three-phase sections, γ(Fe,Ni) Ni7Zr2 Ni5Zr, γ(Fe,Ni) Ni7Zr2 Ni10Zr7, γ(Fe,Ni) Fe2Zr Ni10Zr7, (Fe,Ni)Zr2 Fe2Zr Ni10Zr7, and (Fe,Ni)Zr2 NiZr Ni10Zr7, exist in the isothermal section. No ternary compound is observed.     

Ti掺杂ZrV2合金的相组成及贮氢性能研究

利用真空感应熔炼的方法制备出(ZrTi)V2合金,在950℃下对合金进行长时间的退火处理,对合金的相结构及吸氢性能进行测试。结果表明:(ZrTi)V2合金主要由C15Laves相、α-Zr相、Zr3V3O相和V基固溶体相组成,热处理使得α-Zr相及V基固溶体相减少;该合金经400℃,1h除气之后,再经过一次吸放氢循环即可达到最佳的活化效果;根据Van’tHoff关系外推出室温下该合金的平衡压力为8.1×10-14Pa。     

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.     

锆合金激光熔覆镍基复合层微观组织及界面特征

以Ni35自熔性合金粉末为熔覆材料,采用激光熔覆技术在锆合金表面原位生成了NiZr₂/陶瓷增强镍基涂层.利用金相显微镜、扫描电镜、X射线衍射仪等对熔覆界面附近的微观组织、物相组成及界面结合特征进行分析.结果表明,熔覆层基体组织为NiZr+Ni₁₀Zr₇,增强相NiZr₂以细针状均匀分布在熔覆层上部和底部,块状及棒状的陶瓷相Zr₅（Si_xNi_1-x）₄/Zr（Si_xNi_1-x）分布在熔覆层中部,熔覆层与基体间实现良好的熔焊冶金结合,界面结合区组织不均匀,分布有等轴状NiZr及晶间的α-Zr,熔覆层的显微硬度分布均匀,平均值约为1 100 Hv.     

机械合金化法制备Ni—Zr非晶软磁合金粉末的研究

研究Ni基非晶软磁合金粉末在Ni—Zr二元相图上三个稳定化合物成分配方Ni7Zr2、Ni21Zr8、NiZr和两个共晶点Ni64Zr36、Ni36Zr64组分在机械合金化条件下的非晶合金形成能力和热稳定性。五种配方在一定的时间内都能形成非晶态合金;其中Ni64Zr36的过冷液相区间△Tx达到69．9K。用扫描电子显微镜（SEM）观察了不同球磨时间混合粉末的形貌,发现球磨时间对混合粉末的结构及颗粒形貌存在显著影响。随着球磨时间的增加,Ni、Zr颗粒都发生严重塑性变形,并且通过冷焊团聚起来,形成具有层状结构的复合颗粒。由于磨球的剧烈撞击,使得结构发生了严重的畸变,从而破坏了原有的有序结构而形成了无序结构。另外,在进一步的球磨过程中,合金的晶粒不断减小,形成高体积分数的晶界,而金属粉末不断的发生塑性变形,形成了点缺陷、位错等高密度缺陷,晶格发生严重的畸变,晶体自由能也相应不断上升,最后发生了非晶转变。磁性能测量表明合金粉末具有较好的软磁性能。     

Crystallization behavior of Ti61.67Zr17.15Ni14.80Cu6.38 glass-forming alloy

Ti61.57Zr17.15Ni14.80Cu6.38(atom fraction, %) metallic glass has applications in brazing. Using the hammer-and-anvil technique, Ti61.67Zr17.15Ni14.80Cu6.38 metallic glass was prepared. The crystallization behavior for this metallic glass was investigated by differential scanning calorimetry(DSC), X-ray diffractometry (XRD) and transmission electron microscopy(TEM). There are three stages in DSC curves of crystallization. The reduced glass temperature Trg is 0.42. The kinetic parameters of crystallization were calculated by a set of equations of the maximum crystallization rate. The crystalline phase formed in the MSⅠ(Metastable stage D is Zr2Cu, in the MSII is α-Ti and in the MSⅢ is Ti2Ni. This kind of alloy has lower glass forming ability, and the Ti61.67Zr17.15Ni14.80Cu6.38 metallic glass has lower thermal stability.     

Thermally induced crystallization of Fe73.5Cu1Nb3Si15.5B7 amorphous alloy

Thermally induced crystallization of Fe_73.5Cu₁Nb₃Si_15.5B₇ amorphous alloy occurs in two well-separated stages: the first, around 475 °C, corresponds to formation of α-Fe(Si)/Fe₃Si and Fe₂B phases from the amorphous matrix, while the second, around 625 °C, corresponds to formation of Fe₁₆Nb₆Si₇ and Fe₂Si phases out of the already formed α-Fe(Si)/Fe₃Si phase. Mössbauer spectroscopy suggests that the initial crystallization occurs through formation of several intermediate phases leading to the formation of stable α-Fe(Si)/Fe₃Si and Fe₂B phases, as well as formation of smaller amounts of Fe₁₆Nb₆Si₇ phase. X-ray diffraction (XRD) and electron microscopy suggest that the presence of Cu and Nb, as well as relatively high Si content in the as-prepared alloy causes inhibition of crystal growth at annealing temperatures below 625 °C, meaning that coalescence of smaller crystalline grains is the principal mechanism of crystal growth at higher annealing temperatures. The second stage of crystallization, at higher temperatures, is characterized by appearance of Fe₂Si phase and a significant increase in phase content of Fe₁₆Nb₆Si₇ phase. Kinetic and thermodynamic parameters for individual steps of crystallization suggest that the steps which occur in the same temperature region share some similarities in mechanism. This is further supported by investigation of dimensionality of crystal growth of individual phases, using both Matusita–Sakka method of analysis of DSC data and texture analysis using XRD data.     

ZrOCl_2-Al体系熔体反应生成Al_3Zr_((p)),Al_2O_(3(p))/Al复合材料的反应机制

利用X射线衍射仪 (XRD)和扫描电子显微镜 (SEM ) ,对ZrOCl2 Al体系熔体反应生成的复合材料组织进行了分析 ,结果表明 :ZrOCl2 Al体系反应生成相为Al3 Zr和α Al2 O3 ,颗粒尺寸为 0 .2～ 5 μm ,形状以多面体为主 ;随反应起始温度升高 ,生成的颗粒体积分数增大 ,熔体温度也升高 ,但当熔体温度高于 12 0 0℃时 ,Al3 Zr出现聚集、长大。提出了ZrOCl2 Al体系的反应是气液反应和固液反应的复合过程 ,建立了ZrOCl2 /Al反应中的控制环节ZrO2 /Al反应的动力学模型及化学反应速率的关系式。     

NiZr和NiZr_2共晶温度的测定

有关Ni-Zr二元系中化合物NiZr和NiZr2之间的共晶温度,在热力学计算结果和实验数据之间存在较大差异,对此本文进行了针对性实验测定。利用氩气保护电弧熔炼,在NiZr和NiZr2成分范围内,制备了65wt%、68wt%、72wt%和74wt%Zr的Ni-Zr合金。选用商用氧化铝坩埚和自制氧化锆坩埚,以不同加热速率分别进行了差示扫描量热(DSC)测量,最终确定该共晶温度为1022±5℃。同时对实验合金与坩埚的反应情况进行了热力学分析,证实在测量温度范围内(<1100℃)采用氧化铝坩埚进行相关实验的适用性;在1170℃,氧化锆本身存在由单斜向四方的同素异构转变,氧化锆坩埚适用于该温度以下含锆合金的相平衡与热力学测量。     

Phase stability of bcc Zr in Nb/Zr thin film multilayers

A change in phase stability from hcp Zr to bcc Zr occurs in Nb/Zr multilayers when the bilayer thickness is reduced to the nanometer scale. This phase stability in these multilayers has been described using a model based on classical thermodynamics. Using a previously reported experimental observation of hcp to bcc transformation in these multilayers, a phase stability diagram (referred to as the biphase diagram) has been proposed. Subsequently, a range of multilayers with varying volume fractions and bilayer thicknesses have been sputter deposited. The crystal structures in these multilayers have been determined using X-ray and electron diffraction. The hcp and bcc Zr phases within the Nb/Zr multilayers are in agreement with the predictions afforded by the proposed biphase diagram. The sequence of the Zr bcc phase stability was accomplished by forming its β-Zr (high temperature bcc phase) prior to forming a bcc coherent interface with Nb. First approximations of the structural and chemical contributions to the interfacial energy accompanying the changes in hcp to bcc phase stability for Zr have been evaluated.     

Primary crystallization process of rapidly solidified Al-Ni-Cu-Nd metallic glasses under continuous heating regime

1　INTRODUCTIONManyAl basedamorphous/nanocrystallinealloyscontainingtransitionmetal (TM =Fe ,Co ,Ni,Cu ,etc)andrareearth (RE =La ,Y ,Ce ,Nd ,etc)ele mentshaveanattractivecombinationofmechanicalproperties[13] .InthelasttenyearsawideinterestwasspurredtoresearchprimarycrystallizationofAl richmetallicglasses[4 9] .ThenanophasecompositesofAl TM REsystemcanbeobtainedbyasuitableprocessingcombinationofrapidsolidificationandheattreatment[10 16 ] .Asanimportantwell controlledmethod ,annealin…     

CRYSTALLIZATION OF METALLIC GLASS Zr_70Cu_30 UNDER HIGH PRESSURE

Crystallization temperature of the metallic glass Zr_(70)Cu_(30),observed by X-ray diffractionanalysis,may be increased about 20℃,the superior limit of increase range of thetemperature is about 30℃,under high pressure up to 2GPa.Besides α-Zr and CuZr_2,the Cu_(10)Zr_7 phase was newly obtained as another crystallization product.     

Study on Structural Transformation Behavior of a Ti-Based Bulk Metallic Glass by Thermal Expansion Method

利用真空电弧熔炼和喷铸方法制备了直径为3 mm的Ti40Zr25Ni8Cu9Be18大块金属玻璃棒材。在推杆式热膨胀仪上利用连续升温热膨胀方法研究了该Ti基金属玻璃的结构转变行为。研究发现,该非晶合金的结构转变行为分为5个不同的阶段,分别为弛豫准备阶段,结构弛豫阶段,一级晶化阶段,二级晶化阶段和晶粒长大阶段。TEM观察发现,热膨胀后形成了20 nm左右的纳米晶。研究还发现,该Ti基金属玻璃热膨胀曲线上的特征温度与DSC曲线上的特征温度具有很好的一致性。     

Zr-Al-Co块状非晶的成分优化

运用等电子浓度和变电子浓度线判据实现了Zr—Al—Co块状非晶合金的成分优化．在(Al50Co50)-Zr等电子浓度线(e／α=1．5)和(Zr9Co4)—Al及(Zr78．5Co21．5)—Al变电子浓度线上设计成分，并通过吸铸法制备块状合金．实验结果表明，在(Al50Co50)—Zr等电子浓度线和(Zr9Co4)—Al变电子浓度线上可形成块状非晶合金，且非晶合金的热稳定性与非晶形成能力随电子浓度的增大而单调递增．其中，(Al50Co50)-Zr等电子浓度线和(Zr9Co4)—Al变电子浓度线交点处形成的Zr53Al23．5Co23．5非晶合金，具有最大的热稳定性和非晶形成能力，特征热力学参数Tg=783K，Tx=849K，Tg／Tm=0．637，Tg／Ti=0．590。