Ti对Cu基块体非晶合金的玻璃转变动力学影响

本文选用非晶形成能力高,且在玻璃转变区和过冷液相区有高热稳定性的Cu46Zr47-xAl7Tix(x=0,1.5)块体非晶合金为研究对象。利用X射线衍射分析和差示扫描量热分析(DSC),研究了Ti元素的添加对于Cu基非晶合金玻璃转变动力学的影响。研究结果表明,在Cu46Zr47Al7块体非晶合金中用1.5%的Ti替代Zr之后,利用VFT方程分析得知合金的强度指数D由2.54增大到3.78,脆性指数m也从39减小到34,表现出了更高的玻璃形成能力。     

冷却速度对Cu_(46)Zr_(44)Al_5Nb_5块体非晶合金组织和力学性能的影响

通过磁悬浮熔炼-水冷铜模吸铸法制备了Cu46Zr44Al5Nb5块体非晶合金阶梯形试样,由X射线衍射(XRD),差示扫描量热仪(DSC)和万能试验机分别表征试样的结构、热力学和力学行为,研究其组织、热稳定性和力学性能与冷却速率的关系。结果表明,Cu46Zr44Al5Nb5合金具有较强的非晶形成能力和良好的热稳定性,其热力学行为表现出尺寸效应。熔体凝固冷却速率对试样尺寸变化敏感,随着试样尺寸的增加,冷却速度呈倍数递减、合金结构的无序度下降,原子排列向稳态转变,导致非晶合金的热稳定性降低。合金的玻璃转变温度不是定值,而是随冷却速度增加而升高,过冷液相区宽度ΔTx、约化玻璃转变温度Trg和晶化放热ΔH随直径的增加而降低,玻璃转变温度向低温漂移。随着直径的增加,冷却速度的降低,非晶合金的短程有序范围增大,最近邻原子间距减小,非晶合金结构的无序密堆性下降,原子排列向稳态转变,导致抗压强度降低,合金的断裂强度随试样直径的增大而减小。     

微量元素Y、Ag对Cu基非晶合金玻璃形成能力的影响

采用单辊旋淬法制备了Cu50Zr42Al8,Cu46 Zr47-xAl7Yx(x=2,5),Cu43Zr42AlsAg7和Cu43Zr42Al8Ag5 Y2非晶合金薄带,利用X射线衍射和差示扫描量热分析研究了合金样品的玻璃形成能力和热稳定性.结果表明,在Cu50Zr42Al8中添加适量的Ag、Y后使得非晶合金的短程有序结构发生改变.合金Cu46Zr47-xAl7Yx(x=2,5)的过冷液相区宽度ΔTx分别比Cu50 Zr42 Al8增加了19K、30K,约化玻璃转变温度Trg从0.565分别增加到0.579和0.566,参数γ从0.402分别增加到0.418和0.420,说明Y的添加提高了非晶合金的热稳定性和玻璃形成能力.合金Cu43Zr42 Al8Ag7和Cu43Zr42Al8Ag5Y2与Cu50Zr42Al8相比,约化玻璃转变温度Trg及参数γ均有了明显的提高,达到了0.619、0.416和0.609、0.411,表明Ag的添加、Ag和Y的同时添加均提高了Cu - Zr -Al系非晶合金的玻璃形成能力,但Ag的效果更加显著.     

Al含量对Zr基块体非晶合金力学性能的影响

用铜模吸铸法制备了(Zr64.8/90Cu14.85/90Ni10.35/90)90+xAl10-x(x=-4,-3,-2,0,2,4,6)块体合金,利用X射线衍射仪(XRD)、万能试验机、显微硬度计和扫描电镜(SEM)研究了Al含量对Zr基块体非晶合金力学性能的影响。结果表明:随着Al含量的减小,合金先是从非晶相为主的非晶/晶体复合材料转变为完全非晶材料,接着转变为以晶体相为主的非晶/晶体复合材料,最后转变为完全晶体材料。表明通过调整Al的含量,可以制备出具有完全非晶结构的Zr基块体非晶合金。当x=-2时,即合金成分为Zr63.36Cu14.52Ni10.12Al12时,合金为完全非晶结构,该合金的室温压缩塑性应变达到20.6%,应力-应变曲线体现出了"加工硬化"特性,屈服强度σs、极限强度σm和断裂强度σf分别为1740.6,2030.7和1510.5 MPa。表明通过调整Al的含量,可以制备出具有优良室温压缩塑性的Zr基块体非晶合金。随着Al含量的减小,合金试样的显微硬度的总体趋势为先增大再减小。当x=2时,合金为非晶/晶体复合材料,该合金具有较高的显微硬度HV719.8。     

Cu46Zr44Al5Nb5块体非晶合金的晶化行为研究

通过磁悬浮熔炼-水冷铜模吸铸法制备了Cu46Zr44Al5Nb5块体非晶合金,并研究其变温晶化行为和等温晶化行为,运用Kissinger法和FWO法分别计算出各特征激活能和阶段激活能,考察了不同加热速度下晶化体积分数和晶化温度、晶化激活能的关系,并绘制了TTT曲线并计算非晶形成的临界冷却速率。结果表明,运用Kissinger法得到玻璃转变激活能E g为231.96 kJ·mol-1、晶化初始激活能E x为351.39kJ·mol-1、晶化峰的激活能E p为401.36 kJ·mol-1,Cu46Zr44Al5Nb5BMG具有良好的热稳定性,由TTT曲线计算非晶形成的临界冷却速率约为3.985 K·s-1。晶化类型主要为扩散控制的共晶型转变,随着晶化量的增大,阶段激活能呈减小的趋势。初始晶化阶段的晶化温度较高,主要是形核和微小晶粒的长大,需要克服较大的能量势垒,而随着温度的降低,晶粒的不断形成,晶化过程演变为主要以形核为主,所需要克服的能量势垒相应减小。在T x+100℃等温晶化退火,析出Cu10Zr7和AlCu2Zr共晶相,随着保温时间的延长,析出相的尺寸和体积分数逐渐增加。     

Cu基非晶合金活化过硫酸钠降解酸性橙

采用高级氧化法,以Cu46 Zr44.5 Al7.5 Y2非晶合金为催化剂活化过硫酸钠(PS)降解水中的酸性橙,考察了溶液初始pH值、Cu46 Zr44.5 Al7.5 Y2非晶合金用量、PS初始浓度、温度对降解的影响,以及重复使用过程中的稳定性.结果表明,Cu46 Zr44.5 Al7.5 Y2非晶合金活化过硫酸钠可...     

锆基大块非晶合金的非等温晶化动力学效应

采用非等温差示扫描量热法(DSC)研究了锆基非晶合金Zr60Al15Ni25、Zr65Al10Ni10Cu15的晶化动力学.结果显示,随着升温速率的加快,这两种非晶合金的特征温度Tg、Tx、Tp均向高温区移动,且过冷液相区逐渐加宽,表明非晶合金的玻璃化转变和晶化均具有动力学效应.分别采用Kissinger法和Ozawa法计算各非晶合金的激活能,两种方法的计算结果相近.从激活能数据得出,两种锆基非晶合金的热稳定性均较强;与非晶合金Zr60Al15Ni25相比,Zr65Al10Ni10Cu15虽较难形成玻璃化转变和开始晶化,但其晶化一旦开始则随后的过程反而更容易进行.     

Nb含量对Zr55Cu30Ni5Al10块体金属玻璃热稳定性和力学性能的影响

在水冷铜坩埚中采用铜模吸铸法制备出直径Ф3 mm的(Zr0.55Al0.10Ni0.05Cu0.30)100-xNbx(x=0,2,4,6,8,10)合金试样,利用X射线衍射(XRD)、差热分析(DSC)、扫描电镜(SEM)以及准静态压缩试验方法研究了Nb含量对Zr55Cu30Ni5Al10块体金属玻璃的非晶形成能力、热稳定性、力学性能和组织的影响。研究结果表明,添加适量的Nb元素能提高Zr55Cu30Ni5Al10合金的热稳定性和非晶形成能力。当Nb含量为x=8时,合金具有最宽的过冷液相区(ΔTx=86 K)和最大的非晶形成能力(参数γ=Tx/(Tg+Tl)=0.416)。对于Zr55Cu30Ni5Al10合金,优化Nb元素掺杂量可以获得最佳的非晶形成能力和热稳定性。Nb的适量添加也有利于提高Zr55Cu30Ni5Al10块体金属玻璃的压缩断裂强度和塑性变形能力,其中x=8时,合金的压缩断裂强度和塑性应变量分别达到1877MPa和1.92%,并具有加工硬化现象。     

7N01铝合金热压缩流变行为研究

采用Gleeble-1500D热模拟机进行热压缩变性试验,研究7N01铝合金在变形温度为340 ～460℃、应变速率为0.01～ 10.00 s-1条件下的流变应力行为.结果表明:变形温度和应变速率对合金流变应力有显著影响,流变应力随变形温度的升高而降低,随应变速率的增加而升高;合金在低应变速率(0.01,0.10,1.00s-1)时主要为动态回复软化机制,而在高应变速率(10.00 s-1)时出现动态再结晶软化;7N01铝合金的高温流变行为可用Zener-Hollomon参数描述.     

热压缩2091 Al-Li合金的流变应力行为

采用Ｇｌｅｂｌｅ１５００高温等温压缩试验研究了一种２０９１铝锂合金高温塑性变形时的流变应力行为。结果表明，应变速率和变形温度的变化影响合金稳态流变应力的大小，稳态流变应力与真应力大小无关。应变速率和流变应力之间满足双曲正弦关系，温度和流变应力之间满足Ａｒｈｅｎｉｕｓ关系。可用包含Ａｒｈｅｎｉｕｓ项的ＺｅｎｅｒＨｏｌｌｏｍｏｎ参数描述２０９１合金高温塑性变形时的流变应力行为。     

铜模吸铸与高能球磨制备Zr46Cu46Al8非晶合金的组织结构及晶化动力学研究

采用铜模吸铸法制备出直径3 mm的Zr₄₆Cu₄₆Al₈块体非晶合金, 利用高能球磨法获得了不同粒径的合金粉体, 通过X射线衍射仪、示差扫描量热仪、扫描电镜等测试手段及热力学计算方法, 研究了制备方法对非晶合金组织结构及晶化动力学的影响。结果表明, 块体合金和粉体合金均可获得完全非晶结构; 块体非晶合金玻璃转变和晶化过程具有明显的动力学效应; 单因素变量法制备非晶粉体的最佳参数为: 转速300 r·min-1, 球料比30:1, 球磨时间15 h; 相同条件下, 除过冷液相区外, 块体非晶合金热力学参数普遍高于非晶粉体, 且晶化放热更剧烈; 随着加热速率增大, 二者热力学参数均向高温区移动, 过冷液相区的宽度也逐渐增加; 块体非晶合金和非晶粉体的特征温度表观激活能数值相近, 块体非晶态合金的表观激活能较非晶粉体高, 热稳定性更优。     

过冷处理对Cu45Zr42Al8Ag5非晶热稳定性及力学性能的影响

采用过冷液体等温处理的方法制备出直径为3 mm的Cu45Zr42Al8Ag5合金圆棒,研究了过冷液体等温处理对铜基内生复合材料的热稳定性和力学性能的影响,研究表明,过冷处理后的试样均为原位自生晶体/非晶复合材料,且其有较好的热稳定性.由铜基非晶合金压缩后的应力--应变曲线可以看出,随保温时间的延长,最大抗压强度逐渐降低...     

Fe60CoxZr10Mo5W2B23-x(x=1,3,5,7,9)块状金属玻璃的非晶形成能力

The bulk Fe60CoxZr10Mo5W2B23-x (x= 1, 3, 5, 7, 9) amorphous rods with diameters of1.5 mm were successfully prepared by copper mold casting method with the low purity raw materials.The amorphous and crystalline states, and thermal parameters, such as the glass transition temperature (Tg), the initial crystallization temperature (Tx), the supercooled liquid region (ΔTx = TxTg), the reduced glass transition temperature Trg (Tg/Tm, Tm: the onset temperature of melting of the alloy, and Tg/T1, T1 : the finished temperature of melting of the alloy) were investigated by X-ray diffractometry (XRD) and differential scanning calorimetry (DSC) analysis. Glass forming ability of Fe60CoxZr10Mo5W2B23-x (x=1, 3, 5, 7, 9)bulk metallic glasses has been studied. According to the results, the alloy (x=7) with the highest Trg (Tg/T1 =0. 607, Tg/T1 =0.590) value, has the strongest glass forming ability among these alloys because its composition is near eutectic composition.The wide supercooled liquid region over 72 K indicates the high thermal stability for this alloy system.This bulk metallic glass exhibits quite high strength (Hv 1020). The success of production of the Febased bulk metallic glass with industrial materials is of great significance for the future progress of basic research and practical application.     

冷却介质对退火态Cu50Zr42Al8块体非晶合金力学性能的影响

考察在过冷液相区内790K+30min保温后炉冷和液氮冷却对Cu50Zr42Al8压缩断裂行为的影响。5mm铸态非晶复合棒的屈服强度、断裂强度和杨氏模量分别为1670MPa,1849MPa和104.4GPa,塑性应变为1.9%。经炉冷和液氮冷却试样的压缩断裂强度和杨氏模量下降,分别为912,678MPa和38,56.5GPa。液氮冷却试样为部分非晶结构,炉冷试样完全晶化。晶化相均为正交晶相Cu10Zr7,四角晶相CuZr2和DO3结构的AlCu2Zr三种脆化相。     

Effect of yttrium addition on flow behavior of Cu-Zr-Al bulk metallic glass in the supercooled liquid region

The high temperature deformation behaviors and thermal workability of Cu_(43)Zr_(48)Al_9 and(Cu_(43)Zr_(48)Al_9)_(98)Y_2 bulk metallic glasses in the supercooled liquid region were investigated by the uniaxial compression tests. The results showed that the high temperature deformation behaviors were highly sensitive to strain rate and temperature, and the flow stress decreased with the increase of temperature, as well as with the decrease of strain rate. Additionally, the(Cu_(43)Zr_(48)Al_9)_(98)Y_2 bulk metallic glass displayed smaller flow stress under the same condition. The flow behavior changed from Newtonian to non-Newtonian with increase of the strain rate, as well as the decrease of temperature, which could be explained by the transition state theory. We found that(Cu_(43)Zr_(48)Al_9)_(98)Y_2 bulk metallic glass had better flow behavior than the Cu_(43)Zr_(48)Al_9 bulk metallic glass in the supercooled liquid region. In addition, the processing maps of the two bulk metallic glasses were constructed considering the power dissipation efficiency. The optimum domain for thermal workability of the bulk metallic glass was located using the processing map, where the power dissipation efficiency was larger than 0.8. It was shown that the(Cu_(43)Zr_(48)Al_9)_(98)Y_2 bulk metallic glass, which had larger area of optimum domain, had excellent thermoplastic forming.     

大块锆基非晶合金电化学耐腐蚀行为的试验研究

利用电化学极化曲线方法研究了Zr41Ti14Cu12．5Ni5Be22．5Fe5非晶合金及成分相同的晶化合金及纯Zr在硫酸溶液中的腐蚀行为。利用减重法研究了Zr41Ti14Cu12．5Ni5Be22．5Fe5非晶合金及成份相同的晶化合金在浓硫酸溶液中的腐蚀行为。极化曲线测试结果表明，非晶合金及成分相同的晶化合金与纯金属Zr有很大差异：非晶合金过钝化电位最高，钝化区最长，而纯金属Zr过钝化电位最低；钝化区也最短。减重试验表明，非晶合金的腐蚀速率是成分相同晶化合金的1/4。以上结果表明非晶合金拥有优良的耐腐蚀性能。     

Structural Relaxation, Glass Transition, Viscous Formability, and Crystallization of Zr-Cu–Based Bulk Metallic Glasses on Heating

In this article, we summarize our recent findings on relaxation, glass transition, viscous flow, and crystallization of Zr-Cu?Cbased metallic glasses on heating. At least two processes related to the diffusivities of different alloying elements take place in the glass-transition region of a Zr-Cu-Al-Ni glassy alloy. Also, we report an unusual solidification behavior of the bulk glassy alloy produced using low-purity Zr in which both primary and eutectic-type structural constituents were formed simultaneously during solidification of the melt. In addition, viscous flow and structure changes in the Zr-Cu-Al-Ag glassy alloy are examined in both the glass-transition and supercooled liquid regions. This alloy is found to exhibit localized phase separation leading to nanocrystallization before massive crystallization of the entire sample.     

Preparation and Mechanical Properties of Misch Metal Based Bulk Metallic Glasses

Bulk metallic glasses(BMGs)have been devel-oped in many alloy systems during past decade.Among these systems,rare-earth(RE)metal-basedBMGs are ones of those found earliest and with betterglass forming ability(GFA).For example,La-basedBMGs were the first a…     

Ti基大块金属玻璃的研究与应用

阐述了Ti基大块金属玻璃(BMG)的成分设计原则及制备方法，并对Ti基非晶合金及其部分晶化复合材料的力学性能及断裂机理进行了评述。结果表明：Ti基大块金属玻璃具有较高的断裂强度、弹性延伸率及一定的塑性延伸率，而经过部分晶化获得的非晶合金基纳米颗粒复合材料，其室温塑性获得很大的改善。在此基础上探讨了该合金目前所存在的问题、研究热点以及其应用前景。     

Serrated plastic flow behavior and microstructure in a Zr-based bulk metallic glass processed by surface mechanical attrition treatment

The serrated plastic flow, microstructure and residual stress of a Zr55 Cu30 Ni5 Al10 bulk metallic glass (BMG) undergone surface mechanical attrition treatment (SMAT) have been investigated by a combina-tion of compression tests with scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM) and the incremental hole-drilling strain-gage method.It is found that SMAT leads to various microstructural modifications and residual stress distribution in the surface layers of the Zr-based BMG due to the mechanically-induced nanocrystallization and generation of shear bands.As a re-sult, the BMG alloy exhibits a remarkable work-hardening like behavior and significant increase of plastic strain from less than 1% to 15%, and its plastic deformation dynamics yields a power-law distribution of shear avalanches.Based upon the analysis of the experimental results, it is indicated that this can be con-nected to the SMAT-induced microstructural modifications and the resulting residual compressive stress in the Zr-based BMG.