非晶态合金淬态脆性的研究进展

利用快速凝固技术制备的非晶态合金在某些情况下可表现出淬态脆性,给带村的进一步加工造成困难。本文介绍了国内外有关这一问题的研究进展,尤其是从工艺上改善非晶带材韧性的成果。非晶态合金的淬态脆性有多方面原因：一方面,合金元素、玻璃化元素以及杂质的种类、含量和存在形式等均影响带材的玻璃形成能力和微观结构（短程序）,从而影响脆性。另一方面,冷却速率不足会使得合金在制备过程中即发生结构弛豫,是导致淬态脆性的最主要工艺因素,因此工艺参数如冷却辊的冷却能力、带材剥离温度、带材尺寸和表面质量等对淬态脆性有显著影响,此外母合金熔液的处理方式也在一定程度上影响淬态脆性。     

新型Zr-Al-Ni-Cu块状非晶合金

依据非晶态合金与其相关相具有相近的电子浓度的规律，对Zr-A1-Ni-Cu系进行了电子浓度e／a=1．38的块状非晶成分的设计和制备，获得的块状非晶具有107K的大过冷度，表征非晶形成能力(GFA)的Trg值在0．58-0．64之间，最佳成分为Zr60．6A111．4Nil5．5Cu12.5，其GFA和热稳定性优于Inoue非晶合金，在相同电子浓度下，平均原子尺寸Ra=F0．1486nm，其GFA优于Ra为0．1496和0．1506nm的合金，表明原子尺寸因素对非晶形成能力有重要影响。     

ZrCuNiAl块体非晶合金的玻璃形成能力与动力学行为

利用铜模铸造法制备了Zr53Cu187Ni12Al16.3、Zr519Cu23.3Ni105Al14.3和Zr50.7Cu28Ni9Al12.3块体非晶合金,3种合金形成非晶的最大临界尺寸分别为6 mm、10 mm和14 mm.采用三点压弯式黏度仪、差热分析仪(DTA)研究了上述非晶合金过冷液体的黏度、脆性系数及临界冷却速度对玻璃形成能力的影响.结果表明:在3种合金中,Zr50.7Cu28Ni5Al12.3不仅具有最高的过冷液体黏度,而且具有最低的动力学脆性系数m (51.2)和临界冷却速率Rc(9.8 K/s),这导致该合金具有极强的玻璃形成能力.     

Sn对ZrTiNiCuAl非晶合金玻璃形成能力的影响

研究了固溶元素Sn掺杂对Zr52.5Ti5Ni14.6Cu17.9Al10非晶合金玻璃形成能力（GFA）的影响，结果发现，掺杂不同含量的Sn会使玻璃化温度Tg,晶化温度Tx不同程度地向高温移动，但对合金熔化温度Tm温度不大。当Sn的摩尔分数为1．86％时，合金玻璃化温度Tg提高了17℃，晶化温度Tx提高了36℃，从而使△Tx提高了19℃，玻璃化温度与合金熔点温度的比值Trg由0.63提高到0.65分析了Sn元素对Tg,Tx及玻璃形成能力的影响。     

Zr-Al-Ni-Cu块体非晶合金的成分设计与微结构表征

以等电子浓度和等原子尺寸为判据，设计了6种不同成分的Zr-Al-Ni-Cu合金，用吸铸法制备了上下端直径分别为3和4mm，长度为30mm的合金棒，DSC和DTA结果表明，这些合金均主要由非晶构成，且均具有大的过冷液相区范围ΔTx，高的玻璃转变温度Tg和约化玻璃转变温度Trg。XRD和TEM的结果表明，除了含Cu量（原子分数，％）≥20的2个合金中有少量的晶体相析出外，其余试样中未见晶体相的析出；同时，样品上下端析出的晶体相的种类不同，表明冷速不同对晶体相的种类有影响。     

退火工艺对FeSiB非晶带材脆性的影响

研究了热处理工艺对FeSiB非晶带材韧性的影响情况，结果表明．当退火温度为300℃时，FeSiB非晶带材开始慢慢晶化，当温度上升到500℃时，带材内部结构已由非晶态完全转变成晶态。退火温度对非晶带材的脆化起决定作用，退火温度越高，带材脆化程度越大，250℃是带材脆化的临界温度。当保温时间低于临界脆化时间时，带材脆化程度随时间逐渐上升。保温时间达到临界脆化时间时，带材脆化程度趋于稳定。     

铁基软磁块体非晶合金玻璃形成能力的研究进展

本文首先介绍了当前铁基软磁块体非晶合金的主要研究体系,并重点讲述了合金元素对合金的热稳定性参数如晶化温度Tx、玻璃转变温度Tg及过冷液相区△Tx的影响.铁基非晶合金的玻璃形成能力与△Tx有密切关系并强烈依赖于合金成分.进而总结了合金元素对铁基软磁块体非晶合金的玻璃形成能力影响的一般规律.     

（Fe_（0．99）Mo_（0．01））_（78）Si_9B_（13）非晶合金的低温韧脆性研究

用ＤＳＣ，ＳＥＭ，Ｃｕｒｉｅ温度和电阻测量等多种实验手段研究了非晶条带（Ｆｅ_（０．９９）Ｍｏ_（０．０１））_（７８）Ｓｉ_９Ｂ_（１３）的低温退火脆性．发现其特征脆化温度约为２４４℃，产生了一个有序度增加的结构弛豫过程．同时，伴随有纳米颗位α－Ｆｅ（Ｓｉ，Ｍｏ）多晶组织从非晶基体中析出．进一步提高退火温度，则由于新的有序原子团的出现，自由体积等可动单元再次增大，从而释放应力，恢复韧性．     

非晶态磁性合金和金属玻璃

高硼 (Fe ,Co) (Nd ,Dy) B玻璃合金的软磁性能和热稳定性〔1〕　研究了Fe87-xCo9 5Nd3Dy0 5Bx(x =17 5～ 35 )和Fe6 0 3Co9 2 Nd3Dy0 5B2 5TM2 (TM =Nb ,Ta ,Cr ,Mo和W )玻璃合金过冷液相的热稳定性、玻璃形成能力和软磁性能。采用 99 9%至99 99% (质量 )纯度的纯金属和纯硼 (99 5 % )原料 ,在氩气保护下电弧熔炼制成母合金锭 ,将母合金锭破碎成小块 ,置于石英坩埚中熔化 ,以 35m/s转速的铜轮将熔体旋淬成薄带。另用铜模压力铸造制成不同直径的棒状试样。用X射线衍射法、透射电镜和光学显微镜分析了试样的微观结构。运用差…     

Nd对块体Mg-Cu-Y-Nd非晶合金玻璃形成能力的影响

在非真空熔炼条件下采用工业纯原材料和负压铜模吸铸法制备Mg65Cu25Y10-xNdx(x=0,2,4,6,8,10)棒状试样,利用差示扫描量热(DSC)和X射线衍射(XRD)等方法分析Nd对Mg-Cu-Y-Nd非晶合金玻璃形成能力的影响。结果表明:Nd的含量(x)为0,4,6成分的合金试样具有完全非晶态组织,且x=4时具有最大的玻璃形成能力,其约化玻璃转变温度(Trg)为0.592,过冷液相区宽度(ΔTx)高达66 K;当x为2,8,10时,由于合金成分明显偏离共晶成分,玻璃形成能力降低,试样只含有少量非晶,且主要呈晶体组织特征。     

Evaluation of glass forming ability of alloys

Key step of exploiting a new type BMG (Bulk Metallic Glass) is quickly judging GFA (Glass Forming Ability) of the alloys. The mole melting heats of BMGs are calculated using the weighted averages principle. The reliability and limitation of Trg criterion for CFA are discussed. The reason why Trg of BMGs is larger than 0.5 is discussed. Two new criteria for GFA, △Hmg and △Gg, are proposed. GFA sequence of BMGs is calculated using the △Hmg criterion, the result agrees with that of A. Inoue and the Rc criterion. Furthermore, as an example, the Rc of the alloys developed by Chuang DONG et al is calculated using the △Hmg and △Gg. The ascending sequence of these alloys calculated with the △Hmg criterion agrees with that of Chuang DONG et al. On the contrary, the result by the △Gg criterion is in contrary with Chuang DONG et al, indicating that the △Hmg criterion is better and more convenient than the △Gg criterion. Calculation showed that the optimum △Hmg iS -15.16 k J/mol.     

Compositional optimization of glass forming alloys based on critical dimension by using artificial neural network

An artificial neural network (ANN) model was developed for simulating and predicting critical dimension d_c of glass forming alloys. A group of Zr-Al-Ni-Cu and Cu-Zr-Ti-Ni bulk metallic glasses were designed based on the d_c and their d_c values were predicted by the ANN model. Zr-Al-Ni-Cu and Cu-Zr-Ti-Ni bulk metallic glasses were prepared by injecting into copper mold. The amorphous structures and the determination of the d_c of as-cast alloys were ascertained using X-ray diffraction. The results show that the predicted d_c values of glass forming alloys are in agreement with the corresponding experimental values. Thus the developed ANN model is reliable and adequate for designing the composition and predicting the d_c of glass forming alloy.     

Fragility and glass forming ability of Al-Ni-Ce alloy melts

The fragility of Al-Ni-Ce alloy melts with three kinds of different compositions, Al85Ni10Ce5,Al85Ni8Ce7, Al85Ni5Ce10 (mole fraction, %), was studied using oscillating-vessel viscometer and differential scanning calorimetry. Their fragility parameters obtained from experiments and theoretic calculation are: 238, 228 and 335 respectively. The results indicate that these three kinds of Al-Ni-Ce alloy melts are very fragile liquids, which kinetically show strong non-Arrhenius behaviour in the Angell plot, so they have poor glass forming ability (GFA).The alloy melt AI85NiSCe10 has the largest fragility parameter among the three alloy melts. In the preparation of rapidly quenched amorphous ribbons, AI85Ni10Ce5 and AI85Ni8Ce7 can gain amorphous ribbons when the rotate speed of the roller reaches 800r/min, while for Al85Ni5Ce10 it must exceed 1 000r/min.     

反复熔炼对Zr基大块非晶合金玻璃形成能力的影响

研究了反复熔炼对Zr60Al15Ni25和Zr65Al7.5Ni10Cu17.5合金的玻璃形成能力的影响。DSC分析表明，随着熔炼次数的增多，Zr60Al15Ni25非晶合金的玻璃转变温度和晶化开始温度都提高，而Zr60Al7.5Ni10Cu17.5非晶合金的特征温度基本没有发生变化。Zr60Al15Ni25合金的熔化焓由于反复熔炼而降低，在热力学上有利于非晶相的形成。根据反复熔炼对铸锭凝固组织进而对合金熔体中的短程序的影响，讨论了玻璃形成能力的变化及原子间的结合力对短程序尺寸的影响，分析了2种合金对反复熔炼处理的敏感性的不同。     

Thermal stability and mechanical properties of Gd-Co-A1 bulk glass alloys

The glass forming ability of Gd-Co-A1 ternary alloy systems with a composition ranging from 50% to 70% （molar fraction） for Gd and from 5% to 40% （molar fraction） for AI were investigated by copper mold casting and Gd60Co25Al15 bulk glass alloy cylinders with the maximum diameter of 5 mm were obtained. The reduced glass transformation temperature （TG/Tm） and the distance of supercooling region ATx are 0.616 and 45 K, respectively for this Gd-Co-A1 alloy. The compressive fracture strength （σf） and elastic modulus （E） of Gd-Co-A1 glassy alloys are 1 170-1 380 MPa and 59-70 GPa, respectively. The Gd-AI-Co bulk glassy alloys with high glass forming ability and good mechanical properties are promising for the future development as a new type function materials.     

淬态晶相对块状Zr-Al-Ni-Cu非晶合金疲劳断裂的影响

研究了带有淬态晶相块体非晶合金的对称循环疲劳断裂。结果表明，粗大的晶相促进疲劳裂纹的萌生，而完全非晶试样及带有细小晶相试样的裂纹萌生于样品的表层。非晶基体断口为典型的非晶疲劳条纹。在晶相处为典型的瞬断断口形貌，非晶基体疲劳条纹的间距远大于晶体疲劳条纹的间距。     

Formation and mechanical properties of bulk Cu-Ti-Zr-Ni metallic glasses with high glass forming ability

Bulk amorphous Cu52.5Ti30Zr11.5Ni6 and Cu53.1Ti31.4Zr9.5Ni6 alloys with a high glass forming ability can be quenched into single amorphous rods with a diameter of 5 mm, and exhibit a high fracture strength of 2 212 MPa and 2 184 MPa under compressive condition, respectively. The stress—strain curves show nearly 2% elastic strain limit, yet display no appreciable macroscopic plastic deformation prior to the catastrophic fracture due to highly localized shear bands. The present work shows clearly evidence of molten droplets besides well-developed vein patterns typical of bulk metallic glasses on the fracture surface, suggesting that localized melting induced by adiabatic heating may occur during the final failure event.     

具有高非晶形成能力的高熵合金Cu29Zr32Ti15Al5Ni19

用铜模吸铸法成功地合成了由两个固溶体相构成的高熵合金(HEA) Cu₂₉Zr₃₂Ti₁₅Al₅Ni₁₉和相同成分的非晶态合金(HE-BMG)。实验结果表明该成分的高熵合金具有高的非晶形成能力。铸态高熵合金Cu₂₉Zr₃₂Ti₁₅Al₅Ni₁₉的抗压强度为1127MPa。在750℃保温2小时后的Cu₂₉Zr₃₂Ti₁₅Al₅Ni₁₉高熵合金的硬度仍高达826HV。