Zr41.2Ti13.8Cu12.5Ni10Be22.5合金凝固过程热力学

利用真空冷壁坩埚感应熔炼及铜模离心铸造的方法制备了大尺寸非晶态Zr41．2Til3．8Cul2．5Ni10Be22．5材料，采用DTA和DSC分别研究了该合金的凝固特性及非晶态晶化行为。结果表明：Zr41．2Til3．8Cul2．5Ni10Be22．5合金具有较低的熔点，表现出良好的深共晶特性，在较低的冷却速度下即可制备出大块部分非晶及全部非晶材料。Zr41．2Til3．8Cul2．5Ni10Be22．5大块非晶材料在339．5℃发生玻璃转变，晶化温度为420℃。     

Deformation of Zr41Ti14 Cu12. 5Ni10Be22.5 bulk amorphous alloy under isobaric pressure in super-cooled liquid region

The curve of crystallization transition during continuous heating for the Zr41Ti14 Cu12. 5Ni10Be22.5 bulk amorphous alloy was measured by means of dilatation(Fully automatic transformation recording/measuring instrument) and X-ray diffraction(XRD) method. The deformation behavior of the alloy at various heating rates in the supercooled liquid region was studied. The results show that the glass transition temperature of the alloy increases slightly and the supercooled liquid region(SLR) increases significantly with increasing heating rate. The deformation amount under isobaric pressure of 1 N for the alloy in the SLR increases with increasing heating rate. As the heating rate of the alloy increases from 5 to 100℃/rain, the amount of deformation of the alloy increases from 8.3% to 45%     

搅拌摩擦加工Zr41Ti14Cu12.5Ni10Be22.5大块非晶的组织和性能

研究了搅拌摩擦加工对Zr41Ti14Cu12.5Ni10Be22.5大块非晶的组织和性能影响规律。结果表明：搅拌摩擦加工后非晶合金没有发生晶化。室温下准静态压缩后,母材区﹑热影响区﹑搅拌区试样的抗压强度基本相当,但是搅拌区和热影响区的弹性模量明显提高,搅拌区和热影响区试样断裂前均出现锯齿流变现象,其断口呈现多重剪切特征,认为这与搅拌摩擦加工改变自由体积浓度和分布有关     

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

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氢对Zr41.2 Ti13.8 Cu12.5 Ni10 Be22.5 大块非晶合金晶化特性的影响

利用电弧熔炼及铜模快速铸造的方法制备Zr41.2Ti13.8Cu12．5Ni10Be22．5大块非晶合金，通过电解丙三醇和磷酸的电化学法向大块非晶中充入氢。测试了大块非晶态合金中充入氢的含量及体积变化规律，采用XRD，DSC技术研究了氢对大块非晶的晶化特征的影响。结果表明：Zr41．2Ti13．8Cu12．5Ni10Be22．5大块非晶可充入的氢与金属的摩尔比为0．92，体积膨胀3．5％；随着氢含量的增加，玻璃转变温度和晶化温度稍有提高，并使结晶过程不同阶段的放热峰变弱。     

Structural transformation and rheological processes in bulk metallic glass Zr41Ti14Cu12.5 Ni10Be22.5

The temperature dependence of strain and strain rate of the Zr41Ti14Cu12.5Ni10Be22.5 (Vitl) bulk metallic glass (BMG) under constant heating condition was derived from the static extension method with a dynamic thermal mechanical analyzer (DMA). A few strain rate peaks, which corresponds to the glass transition and multistep crystallization in the differential scanning calorimeter (DSC) examination, were observed in the curves of the relation between strain rate and temperature. The onset of viscous flow and the end of glass transition are interrelated, the first and second strain rate peaks correspond with the first and second crystallization transition processes, respectively.The influence of stress on strain and strain rate was researched. It is found that the rheological behaviour of BMG Vitl changes from elasticity to anelasticity, finally to the Newtonian viscous flow along with increasing temperature.     

Zr41.25Ti13.75Ni10Cu12.5Be22.5多孔块体非晶合金的制备

利用NaCl颗粒作为预制型,U形石英管作为坩埚,在双温区加热电炉中通过快速渗流、水淬和盐型滤除方法制备出直径为8．1mm、高为70mm的Zr基多孔块体非晶合金．XRD分析表明,所制备的样品由单一的非晶相组成．SEM观察表明,孔隙之间具有良好的连通性,孔隙直径和孔棱均小于1mm,多孔非晶合金密度为3．63g／cm^2,孔隙率为40．5％．     

正电子湮没技术研究Zr41Ti14Cu12.5Ni10Be22.5块体非晶合金的结构自由体积

采用X射线衍射(XRD)仪、正电子湮没光谱(PAT)研究Zr41Ti14Cu12.5Ni10Be22.5块体非晶合金的结构特性。结果表明:原始制备的Zr41Ti14Cu12.5Ni10Be22.5块体非晶合金其正电子湮没寿命为176ps(大于正电子在纯铁中点阵空位上湮没的寿命τVFe=165ps)。在过冷液区(T=400℃)等温退火中,正电子湮没寿命随着退火时间的增加而减小。在过冷液区退火,导致Zr41Ti14Cu12.5Ni10Be22.5块体非晶合金的结构更致密。     

Rheological and diffusion behaviours of Zr41Ti14Cu12.5Ni10Be22.5 bulk metallic glass around glass transition

1 Introduction Since the Au-Si metallic glass were firstly prepared by rapid cooling technique in 1960 by DUWEZ et al[1], the study of structure and property of metallic glass has received much attention. The atom transportation behaviors (rheological an…     

Zr41.5Ti14Cu13Ni10Be22.5大块非晶的耐蚀性能

用浸泡法研究了ZrTiCuNiBe大块非晶合金在酸、碱、 盐各种腐蚀性介质中的腐蚀行为.并与典型材料做了比较，结果表明：ZrTiCuNiBe大块非晶合金具有良好的耐蚀性.     

Zr41Ti14Cu12.5Ni10Be22.5块体非晶合金结构自由体积周围化学环境的研究

采用X射线衍射(XRD)、正电子湮没技术(PAT)-多普勒展宽谱,研究Zr41Ti14Cu12.5Ni10Be22.5块体非晶合金及其过冷液相区结构自由体积周围的元素分布.结果表明:原始制备的Zr41Ti14Cu12.5Ni10Be22.5块体非晶合金其结构自由体积周围主要富集Zr原子,在过冷液相区(T＝400 ℃)等温退火后,在该合金结构自由体积周围探测到Zr、Ti和Be原子.     

Zr41.25Ti13.75Ni10Cu12.5Be22.5块状非晶合金的低周疲劳行为

研究了室温完全反向应力控制条件下块状非晶合金Zr41.25Til3．75Nil0Cul2．5Be22．5的低周疲劳行为，结果表明，完全非晶和合晶态相非晶合金均表现为循环稳定直至断裂．完全非晶合金的寿命远高于合晶态相非晶合金．通过试样断裂表面及外表面SEM观察，解释了应变稳定循环产生的机制．两种非晶合金的疲劳断口均可观察到裂纹的萌生、扩展及过载断裂区．合晶态相非晶中的晶态相没有起到阻碍裂纹扩展的作用，而是作为裂纹萌生点或疏松．     

Atomic structure of Zr41.2Ti13.8Cu12.5Ni10Be22.5 bulk metallic glass alloy

Ab initio molecular dynamics (AIMD) calculations were performed on the atomic configuration of Zr_41.2Ti_13.8Cu_12.5Ni₁₀Be_22.5 bulk metallic glass. The local structures were characterized in terms of structure factors (SF), pair correlation functions (PCF), coordinate numbers, bond pairs and Voronoi polyhedra. The glass transition temperature, generalized PCF and SF predicated by AIMD are in good agreement with the experimental data. Icosahedral short-range orders (ISRO) are found to be the most dominant, in view of the presence of the majority of bond pairs with 1551, 1541 and 1431, and Voronoi polyhedra with <0,3,6,1>, <0,2,8,1>, <0,0,12,0> and <0,2,8,4>. Icosahedral medium range orders (IMROs) are formed from icosahedra via the linkage of vertex-, edge-, face- and intercross-shared atoms. The glass structure on the nanometer scale is accumulated by polyhedra through an efficient packing mode. It is suggested that the extraordinary glass-forming ability of this alloy is essentially attributable to the formation of ISRO and IMRO, and the dense packing of atoms.     

氢对Zr41.2Ti13.8Cu12.5Ni10Be22.5块状非晶光谱特性的影响

利用电弧熔炼及铜模快速铸造的方法制备zr41.2Ti13.8cu12．5Ni10Be22.5块状非晶合金，通过电化学方法向块状非晶中充入氢．研究了充氢对该非晶态材料反射光谱、吸收光谱、透射光谱特性的影响．结果表明，充氢掺杂后，提高反射率，降低吸收率，降低红外光的透射率，并使反射峰向短波边移动．     

Zr基大块非晶合金在过冷液相区的静液挤压塑性变形研究

通过Gleeble1500热模拟试验,选择纯铁作为挤压包套材料,然后对非晶合金在390℃、应变速率8.9×10-1s-1的条件下进行了静液挤压。Zr非晶合金产生了塑性变形,但没有发生均匀粘滞性流动,而是断裂成两段。样品断口上随机分布着充分与未充分发展的“脉纹”状切变带,并且断面上出现了类似流动熔体凝固后的特征结构。高应变速率变形条件使非晶合金产生的非均匀流变,以及静液挤压时纯铁先于非晶合金的流动变形是造成非晶合金断裂的主要原因。挤压态非晶合金的过冷液相区减小,热稳定性有所降低。     

氢对Zr41．2Ti13．8Cu12．5Ni10Be22．5块体非晶合金中电子结合能与电阻率的影响

利用电弧熔炼及铜模快速铸造的方法，制备Zr412Ti13.8Cu125Ni10Be225块体非晶合金，通过电化学方法向块体非晶中充入氢。研究了氢对块体非晶合金电子结合能和电阻率的影响。结果表明：氢能够提高非晶合金原子的电子结合能；当氢容量等于29％（摩尔分数，下同）时，电阻率无明显的变化；氢容量等于62％和92％时，电阻率随着氢容量的增加显著降低；并且，充氢使电阻率突变温度降低。     

Zr41.25Ti13.75Ni10Cu12.5Be22.5块体非晶合金的拉伸断裂行为

Zr41．25Ti13.75Ni10Cu12．5Be22．5块体非晶合金在过冷液相区内的拉伸断裂行为与拉伸温度及应变速率有关．在室温条件下拉伸表现为剪切带扩展形成脆性断裂,在断口表面层出现了大量放射状脉状纹络,断口表面层的绝热升温现象导致断裂层温度超过了液相线温度,从而在断面上出现熔融状液滴．在玻璃化转变温度点,断裂模式依然为脆性断裂,韧窝状形貌及脉状纹络代替了放射状的脉状纹络分布于断口表面,同时伴随有熔融状液滴．计算表明,断口表面层绝热升温温度依然高于液相线温度．在更高温度或较低应变速率条件下,断裂方式转变为颈缩断裂模式,在颈缩点顶端依然存在脉状纹络,而未能观察到熔融状液滴．分析表明,在较高温度或较低应变速率条件下,绝热升温对断裂层的影响非常微弱,断口表层的温度没有明显升高．     

Zr基非晶合金在过冷液相区静液挤压的变形行为及结构

研究了Zr41.2Ti13.8Cu12.5Ni10Be22.5非晶合金在过冷液相区内静液挤压的变形行为以及结构变化。结果表明:非晶合金在高应变速率下产生了明显的塑性变形,直径从16 mm变为12 mm,断裂为4段,且样品断口上随机分布着充分发展与未充分发展的脉纹式切变带,由此可看出非晶合金的变形为非牛顿体变形行为;挤压后的样品约有3%的非晶相发生晶化,在非晶基体上析出10~20 nm的纳米晶粒,导致挤压后非晶合金的热稳定性降低;静液挤压高应变速率变形条件使非晶合金产生非均匀流变,是造成非晶合金断裂的主要原因。     

Ductile to brittle transition in the Zr41.2Ti13.75Cu12.5Ni10Be22.5 bulk metallic glass

The variation of impact toughness, Γ, of a Zr_41.2Ti_13.75Cu_12.5Ni₁₀Be_22.5 (Vitreloy-1) bulk metallic glass (BMG) within the temperature range of 123–423 K was evaluated by using an instrumented Charpy impact testing machine, in order to examine if the BMGs exhibit ductile-to-brittle transition (DBT) that is seen in rapidly quenched glasses. Results show an abrupt reduction in Γ when the testing temperature is lowered to below 150 K, implying that the BMGs are also prone to the DBT. Fractographic observations indicate a transition in the fracture mode; from ductile vein-like morphology above DBT to a cleavage-dominant fracture mode below it. Complimentary Vickers indentation measurements show no variation in hardness with temperature. However, the shear banded plastic regions that are typically seen around the indents were observed to be completely absent around the indents that were made at low temperatures, indicating that the inhomogeneous plasticity mediated by shear bands becomes inoperative below a critical temperature resulting in the DBT. This observation suggests that the minimum amount of free volume required for extensive plasticity (and hence high toughness) in metallic glasses is strongly dependent on the temperature. Testing of the structurally relaxed samples (through annealing at 530 K for 2.5 h that induces severe embrittlement at room temperature) at 423 K reveal almost complete recovery of Γ, supporting this hypothesis.     

Zr基非晶合金在过冷液相区的高应变速率压缩变形行为

利用Gleeble1500热模拟机研究了Zr41.2Ti13.8Cu12.5Ni10Be22.5非晶合金在过冷液相区内633、653和673K,应变速率分别为2×10-2s-1和2×10-1s-1条件下的单向压缩变形行为.结果表明:在673 K时两种应变速率下,该合金都具有很好的塑性,尤其在2×10-2s-1时流变应力只有74 MPa,非常适于进行超塑性加工.对非晶合金的断口进行了观察,得到柱状非晶合金压缩变形时外观和断口形貌随着变形条件的变化规律.采用自由体积模型对非晶合金的形变和断裂的微观机制进行了分析.