锆基大块非晶在HCl溶液中的耐腐蚀性研究

利用CHI660B型电化学工作站研究了4种不同成分（Zr55Al10Ni5Cu30，Zr60Al15Ni25，Zr65Al10Ni10Cu15，Xr52．5Al0Ni10Cu15Be12．5）的锆基非晶态合金以及其中两种成分（Zr65Al10Ni10Cu15，Zr52．5Al10Ni10Cu15Be12．5）的晶态合金在2．5mol／L的HCl溶液中的腐蚀行为。通过Tafel曲线的测试结果表明，非晶合金的耐腐蚀性能与其成分有很大的关系，这4种非晶合金试样的耐腐蚀性由强到弱的顺序依次为Zr60Al15Ni25〉Zr65Al10Ni10CU15〉Zr52．5Al10Ni10Cu15Be12．5〉Zr55Al10Ni5Cu30。两种成分的非晶态合金与其对应成分的晶态试样相比，非晶态合金具有较低的腐蚀电流，显示出较好的耐腐蚀性。最后，根据电化学腐蚀原理，从合金的微观结构、化学成分以及腐蚀介质的性质3个方面探讨了影响合金耐腐蚀性的因素。     

Zr-Al-Ni-Cu大块非晶合金的电化学腐蚀行为研究

用电化学方法研究了 6种不同成分的大块非晶合金、与非晶成分相对应的两种晶态合金和纯Zr在 0 .1mol/LNa2 SO4 溶液中的腐蚀行为 ,结果表明 ,6种非晶样品中 ,有 4种具有高耐蚀性能 ,其中 ,成分为Zr65Al7.5Ni10 Cu17.5的样品具有最低的icorr值 1.38× 10 - 2 μA·cm- 2 。两种具有相同成分的非晶与晶态合金相比 ,晶态合金具有更低的icorr值。在 9种实验样品中纯Zr具有最低的icorr值 7.10× 10 - 3 μA·cm- 2 。     

大块非晶合金Zr55Cu30Al10Ni5及其晶态合金的氧化行为研究

采用DSC、TGA、XRD等实验手段研究了大块非晶合金Zr55Cu30Al10Ni5各种状态的氧化行为。结果表明非晶态样品的氧化速率最快,稳定晶化态样品的氧化速率最慢,这说明晶态相Zr2Cu具有良好的抗氧化性。非晶态和晶态样品的氧化动力学均遵循线性规律。     

大块非晶合金Zr55Cu30Al10Ni5的电子结构特征及电击穿行为

测定了大块非晶合金Zr55Cu30Al10Ni5晶化前后的费米能级和各元素的电子结合能，研究了非品合金的电子结构特征和电击穿行为．测试并讨论了非晶材料场发射能力和耐电压强度的关系．结果表明，对于Zr基合金，非品态比品态合金具有更大的功函数．比较了Zr55Cu30Al10Ni5合金非晶态与晶态的耐电压强度数值，发现非晶态合金的耐电压强度数值比较分散，品化合金的耐电压强度相对比较集中．耐电压强度平均值表明，Zr基合金非晶态具有更好的耐电压能力．     

含Be多元合金非晶形成能力的替代效应研究

利用晶胞平移和分子动力学模拟建立了Zr4lTil3.8Be22.5Ni17.5Cu5．2晶态和非晶合金的原子结构模型，利用递归方法研究了Zr4lTi13.8Be22．5Ni17．5Cu5．2晶态及非晶态合金中元素的替代效应．Be与B、Al、Si状态密度形状相似表明Be与B、Al、Si具有相似的性质，可以用Al、B、Si代替Be；非晶态相对于晶态的结构能差表明，用Al、B、Si代替Be后均使合金的非晶形成能力下降，只是Al、B下降的幅度较小；用Al、B替代Be，再用其它过渡金属替代Cu、Ni或zr、Ti可使非晶形成能力达到含Be合金的水平．     

机械合金化Zr-Al-Ni-Cu-Ag非晶合金的晶化行为

研究了机械合金化非晶态Zr65Al7.5Ni10Cu7.5Ag10合金的晶化过程，由于存在扩散不均匀区，机械合金化非晶合金在深过冷液相区的退火组织不同于快淬合金，在深过冷液相区退火，析出二十面体准晶相及一些知相：在靠近第一个放热峰的温度退火，近出Zr2Cu相：第二个放热峰对应残余非晶相及准晶相向Zr2Ni,Zr2-Al3的转变。     

新型Zr57Nb5Cu15.4Ni12.6Al10大块非晶态合金的制备及其室温单轴压缩断裂行为

应用铜模真空吸铸法制备直径达5mm的棒状新型Zr57Nb5Cu154Ni12.6Al10大块非晶样品.X射线衍射检测证明样品完全为非晶态.通过等温示差扫描量热法(DSC)测试了Zr57Nb5Cu15.4Ni12.6Al10大块非晶的晶化动力学效应,同时研究了大块非晶合金的室温单轴压缩变形和断裂行为.结果表明:Zr57Nb5Cu15.4Ni12.6Al10块体非晶晶化过程具有动力学效应;其室温压缩变形过程主要表现为弹性变形;断裂面与压缩方向约呈45°,断口呈现典型的脉状花样.     

超声波筛选激光增材制造非晶合金

目的 快速优化出无缺陷非晶合金激光增材制造工艺。方法 以Zr51Ti5Cu25Ni10Al9非晶合金为模型材料,利用超声波对金属内部缺陷的衰减,来快速筛选激光增材制造非晶合金的最佳工艺组合(激光功率和扫描速度)。结果 超声波检测可以准确有效地检测出非晶合金试件的晶化比例,并且当激光功率为1 300 W、扫描速度为600 mm/min时超声波衰减系数降至最低。进一步对该工艺下获得的样品分析发现,该工艺成型的Zr51Ti5Cu25Ni10Al9非晶合金缺陷最少、晶化程度最低、性能最佳。结论 超声波技术是快速筛选激光增材制造非晶合金等高性能金属最佳工艺参数的有效技术手段。     

Zr基大块非晶合金成分的等电子浓度和等原子尺寸判据

制备了6种合金Zr65.5Al5.6Ni6.5Cu22.4,Zr65.3Al6.5Ni8.2Cu20,Zr65Al7.5Ni10Cu7.5,Zr64.8Al8.3Ni11.4Cu5.5,Zr64.5Al9.2Ni13.2Cu13.1和Zr63.8Al11.4Ni17.2Cu7.6,共晶成分位于合金Zr64.5Al9.2Ni13.2Cu13.1和合金Zr63.8Al11.4Ni17.2Cu7.6的成分之间，这6种合金均显示了非晶相的形成和较宽的过冷液相区范围△Tx值，以及较大的约化玻璃转变温度Trg值，除合金Zr63.8Al11.4Ni17.2Cu7.6的△Tx值为87K外，其余5种成分合金的△Tx值均在97K以上，最宽的达105K，表明这6种合金是一个具有大玻璃形成能力和高热稳定性的非晶合金系列，合金Zr63.8Al11.4Ni17.2Cu7.6是6种合金中玻璃表成能力和热稳定性最高的，其Tg，Tx和Trg值最高，Inoue非晶合金Zr65Al7.5Ni10Cu17.5并不是最佳非晶成分，提出以等电子浓度和等原子尺寸规律作为设计大块非晶合金成分的判据。     

弛豫对Zr-Al-Ni-Cu基非晶合金晶化过程的影响

非晶合金的稳定性是制备大块非晶合金的关键，而弛豫后形成的短程有序结构对非晶中的晶体相形核有重要的影响。本文通过差热分析及X射线衍射法研究了预先弛豫处理对Zr60Al8Ni12.5Cu17Si2.5和Zr60Al8Ni10Cu17Si5非晶合金晶化过程的影响。结果表明：预先弛豫处理降低了上述非晶合金的稳定性。Si含量的增加则提高上述非晶合金的稳定性。根据等温转变过程日体相形核孕育期采用Arrhenius公式所确定的晶化激活能更能反映非晶晶化过程及非晶的稳定性。     

Effect of Minor Alloying on Crystallization Behavior and Thermal Properties of Zr_(64.5)Ni_(15.5)Al_(11.5)Cu_(8.5) Bulk Amorphous Alloy

Minor alloying plays an important role in the synthesis and improvement of thermal stability of bulk metallic glasses(BMGs).The present study was conducted to investigate the effect of minor additions of Y,Ti and Nb on the crystallization behavior and the thermal properties of Zr64.5Ni15.5Al11.5Cu8.5 alloy.Thermal parameters and the activation energies for crystallization were calculated for four(Zr0.645Ni0.155Al0.115-Cu0.085)100-xMx(M=Y,Ti and Nb,while x=0,2 at.) alloys.The present alloys have wide supercooled liquid region of ≥87 K.Maximum activation energy was found to be greater than 300 kJ/mol for the base alloy.Four crystalline phases were identified in the samples annealed at 823 K for 20 min.Reduced glass transition temperature(Trg) and other thermal parameters such as γ,δ and β were improved by Y and Ti addition.Nb addition resists crystallization below annealing temperature 713 K,however,its effect on thermal properties is not very promising.     

Crystallization Behaviour and Mechanical Properties of Zr65Cu18Ni9Al8 Bulk Metallic Glass

Designing and synthesis of cost effective bulk metallic glasses (BMGs) has been of considerable interest during the last decade so that they can be made commercially viable. Among these, Zr-based BMGs have been reported extensively due to their attractive properties. An alloy having composition Zr65Cu18Ni9Al8 was designed and synthesized using 2-3 N pure materials by Cu mould casting. The alloy was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and high temperature differential scanning calorimetry (DSC). Thermal parameters like supercooled liquid region ΔTX, reduced glass transition temperature Trg, γand σ parameters were evaluated. Mechanical properties like microhardness, nanohardness, elastic modulus and fracture strength were measured. The alloy showed wide supercooled liquid region of 129±1 K with improved thermal stability. The alloy has considerable fracture strength along with fair amount of ductility.     

Crystallization Behaviour and Mechanical Properties of Zr65Cu18Ni9A18 Bulk Metallic Glass

Designing and synthesis of cost effective bulk metallic glasses （BMGs） has been of considerable interest during the last decade so that they can be made commercially viable. Among these, Zr-based BMGs have been reported extensively due to their attractive properties, An alloy having composition Zr65Cu18Ni9A18 was designed and synthesized using 2-3 N pure materials by Cu mould casting. The alloy was characterized by X- ray diffraction （XRD）, scanning electron microscopy （SEM）, energy dispersive X-ray spectroscopy （EDS） and high temperature differential scanning calorimetry （DSC）. Thermal parameters like supercooled liquid region △Tx, reduced glass transition temperature Trg, γ and δ parameters were evaluated. Mechanical properties like microhardness, nanohardness, elastic modulus and fracture strength were measured. The alloy showed wide supercooled liquid region of 129＋1 K with improved thermal stability. The alloy has considerable fracture strength along with fair amount of ductility.     

Gibbs Free Energy and Activation Energy of ZrTiAlNiCuSn Bulk Glass Forming Alloys

The Gibbs free energy differences between the supercooled liquid and the crystalline mixture for the (Zr_(52.5)Ti_5Al_(10)-Ni_(14.6)Cu_(17.9))_((100-x)/100)Sn_x (x=0, 1, 2, 3, 4 and 5) glass forming alloys are estimated by introducing the equationproposed by Thompson, Spaepen and Turnbull. It can be seen that the Gibbs free energy differences decrease firstas the increases of Sn addition smaller than 3, then followed by a decrease due to the successive addition of Snlarger than 3, indicating that the thermal stabilities of these glass forming alloys increase first and then followed by adecrease owing to the excessive addition of Sn. Furthermore, the activation energy of Zr_(52.5)Ti_5Al_(10)Ni_(14.6)Cu_(17.9) and(Zr_(52.5)Ti_5Al_(10)Ni_(14.6)Cu_(17.9))_(0.97)Sn_3 was evaluated by Kissinger equation. It is noted that the Sn addition increases theactivation energies for glass transition and crystallization, implying that the higher thermal stability can be obtainedby appropriate addition of Sn.     

具有大过冷液相温度区间的Cu基大块非晶合金的制备和机械性能

利用铜模铸造方法制备了具有大过冷液相温度区间的Cu-Zr-Ti-Ni系高强度Cu基大块非晶合金,对于Cu55Zr55Ti15Ni5合金,最大直径达5mm.过冷液相区温度范围ΔTx达45.48～70.98 K.Cu基玻璃合金棒表现出非常高的机械性能和明显的塑性,对于Cu50Zr25Ti15Ni10、Cu55Zr25Ti15Ni5和Cu54Zr22Ti18Ni6合金,压缩断裂强度分别达2155MPa、2026MPa和1904MPa,维氏硬度分别达674、678和685.加入Co元素扩大了CuZr-Ti-Ni系合金的ΔTx,Cu50Zr22Ti18Ni6Co4合金的ΔTx高达74.5K.     

Complete Composition Tunability of Cu(Ni)-Ti-Zr Alloys for Bulk Metallic Glass Formation

In the Cu-Zr-Ti ternary system, a new composition zone of bulk metallic glasses (BMGs) formation was discovered, locating at the 55-57 at. Pct Cu, 30-31 at. Pct Ti and 13-14 at. Pct Zr, and near Cu-Ti binary subsystem rather than the Cu-Zr binary. For these alloys, BMG rods of 2 mm in diameter can be fabricated by using copper mould casting. It is expected that these BMG-forming alloys correlate with (L→CuTi+Cu2TiZr+Cu61Zr14) eutectic reaction that the undercooled melt undergoes during solidification. Adopting "3D pinpointing ap-proach", compositional dependence of glass-forming ability (GFA) in Cu(Ni)-Ti-Zr pseudo ternary system was revisited. Optimized BMG-forming composition is located at Cu50.4Ni5.6Ti31Zr13, with a critical diameter of 6 mm for complete BMG formation. Its GFA is significantly superior to Vit 101 (Cu47Ni8Ti34Zr11) previously developed by Caltech group. The effect that the GFA of the ternary base alloy was improved by substitution of Ni for Cu is attributed to a role of retarding the crystallization of Cu51Zr14 intermetallics.     

Microstructure and bond strength of Ni–Cr steel/Al2O3 joints brazed with Ag–Cu–Zr alloys containing Sn or Al

Abstract

Sintered Al₂O₃ was joined to Ni–Cr steel by the active metal brazing route with Ag–Cu–Zr brazing alloys containing Sn or Al. A single ZrO₂ layer with a monoclinic structure was formed at the Al₂O₃ /brazement interface by the migration of Zr in the molten brazing alloy to the Al₂O₃ surface, followed by a redox reaction between the Al₂O₃ and Zr. The remainder of the brazement formed a Cu–Ag eutectic alloy. Precipitates CuZr₂ and Cu–Zr–Al were formed in the brazements of the Ni–Cr steel/ Al₂O₃ joints brazed with Ag–Cu–Zr alloys and Al containing Ag–Cu–Zr alloys, respectively. On the other hand, no precipitates were formed in the brazement of the Ni–Cr steel/Al₂O₃ joints brazed with Sn containing Ag–Cu–Zr alloys. The Ni–Cr steel/ Al₂O₃ joints brazed with Sn containing Ag–Cu–Zr alloys showed much higher fracture shear strengths than those brazed with Ag–Cu–Zr alloys or Al containing Ag–Cu–Zr alloys.