稀土元素对Cu基非晶合金形成能力和力学性能的影响

通过铜模铸造法成功制备出直径分别为5 mm和3 mm的三元Cu45Zr48Al7和四元Cu45Zr45Al7Y3大块非晶合金。采用甩带法制备了Cu42Ni8Ti48Sm2、Cu42Ni8Ti48Y2、Cu42Ni8Ti48Gd2三种条带非晶;其中,Cu42Ni8Ti48Y2合金的非晶形成能力最强。三种非晶的玻璃转变温度Tg不十分明显,在冷却过程中存在着一定浓度的初晶相预存核,过冷液相区ΔTx不能反映该合金系非晶形成能力的差异。Cu47Zr42Al6Y5和Cu47Zr42Al6Er5合金组织基本由非晶相组成;Cu47Zr42Al6La5合金组织含有较多的晶态相,其压缩断裂强度较低;压缩断裂机理为解理 穿晶。     

Nb对Cu基非晶合金热加工及力学性能的影响

为了提高Cu基非晶合金的热加工性能和力学性能,采用铜模铸造法制备了直径为2 mm的Cu47Zr47-xAl6Nbx非晶合金.分别利用X射线衍射仪、扫描电子显微镜、差示扫描量热计和电子万能试验机对Cu47Zr47-xAl6Nbx非晶合金的相组成、显微组织、热力学参数和力学性能进行了研究.结果表明,适量的Nb元素可以提高Cu47Zr47-xAl6Nbx非晶合金的热加工和力学性能.Cu47Zr47Al6非晶合金的过冷液相区和断裂强度分别为53.5 K和1 528 MPa.当Nb元素的原子分数为2%时,Cu47Zr45Al6Nb2非晶合金具有最大的过冷液相区和断裂强度,且可以分别达到69.0 K和1 830 MPa.     

工业原料制备Zr-Cu基非晶合金及其压缩断裂行为研究

采用工业原料制备了Φ4 mm的Zr55Cu30Ni5Al10非晶合金棒材,利用XRD,DSC,SEM分析了该合金体系玻璃形成能力及压缩断裂行为.结果表明:Zr55Cu30Ni5Al10非晶合金棒材在10,15,20 K/s的升温速度下,过冷液相区△Tx分别为71.2,72.4,68.1 K,具有较大的玻璃形成能力.该非晶合金棒材抗压强度达到1 702 MPa,断口微观形貌为典型的脉络状花纹,在断口与试样连接处发现大量的剪切带存在,同时还产生了局部熔化现象.     

添加微量稀土钇对铜基合金非晶形成能力的影响

针对铜基非晶合金玻璃形成能力问题,分析了添加微量稀土元素Y对合金的玻璃形成能力、热稳定性的影响,利用铜模吸铸法制备出Cu-Zr-Al-Y9mm非晶合金.研究结果表明：制备的9mm铜基非晶合金试样（Cu45Zr47Al8）97Y3,在过冷液相区ΔT和约化玻璃转变温度Trg分别是79.42K和0.775 3.随着稀土元素Y含量的增加Trg值变小,合金的非晶形成能力降低,通过Trg值变化可以判别该合金的非晶形成能力.     

微量Ta对Cu-Zr-Al合金玻璃形成能力及力学性能的影响

含Ta颗粒的非晶复合材料除具有高强度、高硬度等非晶材料的特性外,塑性也显著提高,比单一的非晶态材料更加具有工程应用价值.文中采用铜模吸铸法制备出直径为3mm的(Cu47Zr47A16)100-xTax(x=0,1,2,3,4,5)块体非晶合金.采用X射线衍射对合金的组织结构进行了分析.通过差示扫描量热法研究了微量Ta对Cu-Zr-Al块体非晶合金玻璃形成能力的影响.对合金进行了压缩测试,并通过扫描电子显微镜观察了断口形貌.实验结果表明:微量Ta的加入能提升Cu-Zr-Al合金的玻璃形成能力及其热稳定性,当加入量为3at.%时效果最为明显.Ta含量达到5at.%时,合金的玻璃形成能力显著恶化.溶入微量Ta使Cu-Zr-Al非晶的断裂强度显著上升,(Cu47Zr47A16)97Ta3的抗压强度达到2 149MPa.Ta对Cu-Zr-Al非晶合金的塑性影响不大,(Cu47Zr47A16)100-xTa仍是典型的脆性材料.     

钇对ZrCuNiAl系合金非晶形成能力的影响

利用X射线衍射（XRD）和差示扫描量热分析（DSC）研究了添加钇对Zr55 Cu30Ni5Al10Y（=0,1,2,3,4）非晶合金体系玻璃形成能力的影响。用铜模铸造获得的Zr55-xCu30Ni5Al10Y（=0,1,2,3,4）块体非晶合金的临界尺寸从直径6 mm增加到20 mm。分析认为,微量钇的添加可以与合金中的残留氧形成氧化物,降低氧对合金形成非晶态结构的负面效应。因此添加适量的稀土元素钇有利于提高Zr55 Cu30Ni5Al10Y非晶合金体系的玻璃形成能力。     

(Zr52.5Ti5Al10Ni14.6Cu17.9)(100-x)/100Snx系合金非晶形成能力分析

采用电弧熔炼铜模吸铸工艺制备了（Zr52.5 Ti5 Al10 Ni14.6 Cu17.9）(100-x)/100 Snx，系大块非晶合金，对掺杂元素Sn对大块非晶合金玻璃形成能力的影响规律进行了分析探讨．研究结果表明，（Zr52.5 Ti5 Al10 Ni14.6 Cu17.9）(100-x)/100 Snx，系大块非晶合金玻璃形成能力判据参数过冷液相区和玻璃约化温度(△T，Trg)呈现随Sn质量分数的增加而先增加后降低的规律，在Sn质量分数为3％时达到最大值，对应于最佳成分．并初步分析了元素Sn掺杂提高玻璃形成能力的机理．     

Fe对Zr55Al10Ni5Cu30非晶形成能力及力学性能的影响

为了进一步提高锆基大块非晶合金的玻璃形成能力及力学性能,采用铜模吹铸法制备了（Zr0.55Al10Ni0.05Cu0.30）100-xFex（X=1,5,10）系列合金,通过X射线衍射（XRD）、差示扫描量热法（DSC）以及压缩实验和SEM进行材料分析。研究表明：微量Fe有助于改善非晶合金在压缩变形时剪切带内的应力分布,提高材料的综合性能,当Fe添加量为1％时,塑性应变εp达到5．9％,强度达到1．89GPa,同时,随着Fe添加量的增加,过冷温度区间ΔTx减小,热稳定性减小,非晶形成能力降低。     

块体(Zr0.6 Cu0.2 Ni0.1 Al0.1)100-xTix非晶合金熔体玻璃形成能力

以合金元素掺杂法考察了Ti质量分数对(Zr0．6Cu0．2Ni0．1Al0．1)100-xTix(x=1．5，3，…，7．5)块体非晶合金玻璃形成能力的影响．结果发现，随着Ti质量分数的增加，非晶合金的过冷液相区温差△Tx逐渐减小，而约化玻璃温度Trg逐渐增加，对应的楔形试样中非晶区的最大厚度(dm)逐渐增加，表明Ti的加入可以明显的提高非晶形成能力．在Ti含量为6％时(对应成分：Zr56.4Cu18.8Ni9.4Al9.4Ti6)合金具有最好的玻璃形成能力．以上结果预示着Zr56.4Cu18.8Ni9.4Al6Ti16合金具有良好的玻璃形成能力．     

Zr63Al10Ni10Cu14Nb3大块非晶合金的力学行为研究

通过电弧熔炼并利用吸铸的方法制备了长70 mm、直径3 mm的Zr63Al10Ni10Cu14Nb3大块非晶合金.热稳定性分析表明:该合金具有较大的过冷液相区.室温压缩实验显示合金具有很高的屈服强度,在合金发生屈服之后应力-应变曲线上有明显的锯齿现象和一个明显的应变软化阶段.结合断口形貌特征,分析并讨论了非晶合金的剪切断裂机理.     

Cu—Zr—Al大块非晶合金的制备及性能研究

采用铜模铸造的方法制备了Cu48Zr52-x Alx（x=6,7,8,9,10,at％）几种合金奠射线衍射（XRD）实验检验Cu48Zr44Al8,Cu48Zr43Al两种合金样品为完全非晶态．对样品进行差示扫描量热分析（DSC）考查三种大块非晶合金的非晶形成能力,以及灿的添加对非晶形成能力的影响．结果表明：当铝含量X=9时,合金的非晶形成能力及热稳定性最好．     

锆基非晶合金在NaOH溶液中的腐蚀行为

用电化学极化曲线研究锆基非晶合金Zr53.5Cu26.5Ni5Al12Ag3在25℃和60℃温度下,在0.01 mol/L和0.1 mol/L的NaOH溶液中腐蚀100 h的腐蚀行为,并用金相显微镜和扫描电镜对腐蚀前后试样的表面形貌进行观察与分析.极化曲线的测试结果表明：锆基非晶合金在25℃下,在浓度为0.01 mol/L和0.1 mol/L的NaOH溶液中浸泡100 h,随着NaOH溶液浓度的升高,非晶合金的耐腐蚀能力下降;锆基非晶合金在25℃和60℃下,在浓度为0.01 mol/L的NaOH溶液中浸泡100 h,随着NaOH溶液温度的升高,非晶合金的耐腐蚀能力下降;锆基非晶合金和晶态合金在60℃下,在浓度为0.1 mol/L的NaOH溶液中浸泡100 h,非晶合金的耐腐蚀性能优于晶态合金.最后根据电化学腐蚀原理,从腐蚀介质温度和浓度方面的性质探讨锆基合金耐蚀性能的因素.     

Effects of small amount Ta on the characteristics ofthe Zr-Al-Ni-Cu-Ta bulk metallic glass

The effects of Ta on the characteristics of the Zr-base BMG (bulk metallic glass) were investigated. Zr55Al10Ni5Cu30-xTax(x=1,2,4) bulk metallic glasses (BMGs) with 3.5 mm diameter and 70 mm length were successfully prepared by using combined jet and copper mold casting. A small amount of Ta addition does not change the glass transition temperature, crystallization temperature, and supercooled liquid region obviously, but Ta promotes composition separation and two-stage crystallization. The stable crystalline phases include ZrENi, CuZr2, AlEZr3 intermetallic compounds and Ta-rich solid solution after annealing the Zr-Al-Ni-Cu-Ta alloys at 753 K. Zr55Al10Ni5Cu30-xTax (x=1,2,4) bulk glassy alloys exhibit a better compressive strength. The stress-strain curve shows a zigzag feature, and the fracture surface shows intersecting of shear bands. It may correlate with the inhomogeneous feature of amorphous structure.     

Si_3N_4-doped Zr_(50)Al_(15)Ni_(10)Cu_(25) glassy alloy by mechanical alloying and sintering process

Zr50Al15Ni10Cu25 amorphous powder was synthesized by mechanical alloying.The effect of Si3N4 addition on the crystallization behavior of the alloy during sintering process was studied.Thermal stability of the powders was performed by differential scanning calorimetry(DSC).The phase and microstructure of the powders and bulk specimens sintered were determined by X-ray diffractometry(XRD) and scanning electron microscopy(SEM).The results show that,introducing 0.05%(mass fraction) Si3N4 can enhance the crystallization activation energy of the Zr50Al15Ni10Cu25 amorphous powders,which indicates that Si3N4 addition has hindrance effect on forming crystals from Zr50Al15Ni10Cu25 amorphous powder.However,0.10% Si3N4 results in the decrease of the crystallization activation energy,which makes its crystallization process easy to occur.     

Al-Ni-Y三元合金玻璃形成能力及热稳定性

为了分析Al-Ni-Y三元合金的玻璃形成能力和热稳定性,采用熔体急冷法制备了Al₉₀Ni₂Y₈、Al₈₇Ni₅Y₈、Al₈₄Ni₈Y₈和Al₈₀Ni₁₂Y₈合金条带.利用x-射线衍射（XRD）表征了急冷态和部分晶化后条带的结构,运用示差扫描量热仪（DSC）分析了合金的玻璃转变和晶化行为.结果表明：除了Al₈₀Ni₁₂Y₈和Al₉₀Ni₂Y₈合金外,制备态的条带均为完全非晶态,部分晶化后有纳米铝晶体析出;Al₈₄Ni₈Y₈合金DSC曲线上可以明显地观察到玻璃转变温度Tg.〖JP2〗通过比较4种合金的热稳定性,发现随着Ni的原子分数升高,合金的初始晶化温度Tx也随着升高,合金的热稳定性增强.     

Compositional dependence of thermal and elastic properties of Cu-Ti-Zr-Ni bulk metallic glasses

Starting from the quaternary Cu47Ti34Zr11Ni8 alloy, the compositional dependence of thermal and elastic properties of Cu-Ti-Zr-Ni alloys was systematically investigated. Quaternary Cu-Ti-Zr-Ni alloys can be cast directly from the melt into copper molds to form fully amorphous strips or rods with the thickness of 3-6 mm. The evidence of the amorphous nature of the cast rods was provided by X-ray spectra. The measured glass transition temperature (Tg) and crystallization temperature (Tx) were obtained for the alloys using differential scanning calorimetry (DSC) at the heating rate of 20 K/s. In the results, the differences between the glass temperature and the crystallization tempera-ture (△Tx=Tx-Tg) are measured with values ranging up to 33-55 K. The reduced glass transition temperature (Trg), which is the ratio of the glass temperature to the liquidus temperature (T1), is often used as an indication of the glass-forming ability of metallic alloys. For the present Cu-Ti-Zr-Ni alloys, this ratio is typically in the range of 0.5838-0.5959, characteristic of metallic alloys with good glass-forming ability. The elastic constants for several selected alloys were measured using ultrasonic methods. The values of the elastic shear modulus, bulk modulus, and Poisson's ratio were also given.     

Ti50Cu42Ni8非晶合金力学性能与晶化组织的研究

采用铜模喷注法成功制备出成本较低直径为2mm的Ti50Cu42Ni8大块非晶合金,对其力学性能及铸态与晶化显微组织进行了研究。结果表明：Ti50Cu42Ni8非晶合金具有优异的力学性能,压缩断裂强度可达2008MPa,弹性模量为100GPa,非晶样品的断裂面与轴向成45。,断口出现河流状脉纹及熔滴。其铸态显微组织为无特征组织,480℃和650℃退火后分别出现条状和梅花状晶态相。     

Chemical short-range order domain in bulk amorphous alloy and the prediction of glass forming ability

Since the discovery of bulk Zr-Ti-Cu-Ni-Be[1] and Pd-Ni-Cu-P[2] metallic glasses with ex-traordinary high glass forming (GFA) ability and critical cooling rate lower than 100 K/s, great attention has been paid to the structure of BMG alloys. Experimental results of X-ray and neutron diffraction or scattering have provided ample evidence that there is a short-range order in BMG alloys. Metallic glasses always exhibit strong compound forming tendency and the corresponding anomalies of t…