scholarly journals Application of 3D Balanced Growth Theory to the Formation of Bulk Amorphous Alloys

2021 ◽  
Vol 8 ◽  
Author(s):  
YaQi Wu ◽  
Yong Zhang ◽  
Tao Zhang
Keyword(s):  
Amorphous Alloy ◽  
Cooling Rate ◽  
Amorphous Alloys ◽  
Three Dimensional ◽  
Thin Strip ◽  
Growth Theory ◽  
Bulk Amorphous Alloy ◽  
Balanced Growth ◽  
Bulk Amorphous Alloys ◽  
Size Limitation

Since the emergence of amorphous alloys as a new class of materials, efficiency improvements have been made in optimizing the fabrication process, the mechanization of alloy formation, and the size of the alloys themselves. Amorphous alloys have been used in precision instruments as they possess excellent magnetic properties, corrosion resistance, wear resistance, high strength, hardness, toughness, high electrical resistivity, and electromechanical coupling properties. Because their hysteresis losses are lower than those of traditional transformer cores, the conversion efficiency of equipment has been significantly improved, thereby saving energy and protecting the environment. Hence, amorphous iron cores have replaced traditional materials. Amorphous alloys also show excellent performance as anti-corrosion and wear-resistant coatings. The process of preparing amorphous alloys starts with an amorphous alloy film obtained by evaporation deposition and then proceeds to the use of a high cooling rate ribbon spinning method to finally obtain a thin strip of an amorphous alloy. A widely used method of copper mold suction casting is then used to prepare the bulk amorphous alloy. The sizes of amorphous alloys have been continually increasing, which has resulted in increasingly serious challenges, such as cooling rate and thermal stability limitations. In addition, crystals can form at low cooling rates. The latent heat of crystallization is released when crystals are formed, which causes damage to the amorphous area so that the size of amorphous alloys is reduced. Because of these difficulties, new processes that eliminate the cooling rate gradient, such as 3D additive manufacturing, ultrasonic production, and mold design, combined with the concept of “entropy control” component design and the economic theory of “balanced development,” lead to a three-dimensional bulk amorphous alloy being proposed. The theory of balanced growth provides a new concept for the development and application of bulk amorphous alloys. This review offers a retrospective view of recent studies of amorphous alloys and provides a description of the formation of amorphous alloys and amorphous phases and the criteria required to predict the successful formation of amorphous alloys. Then, we address the problem of size limitation confronting current production methods. The three-dimensional balanced growth theory of bulk amorphous alloys was formulated from a flexible adaptation of the balanced growth theory of economics. We have confidence that the production and development of bulk amorphous alloys have a bright future.

Design of a bulk amorphous alloy containing Cu–Zr with simultaneous improvement in glass-forming ability and plasticity

2007 ◽  
Vol 22 (2) ◽  
pp. 486-492 ◽  
Author(s):  
Seok-Woo Lee ◽  
Sang-Chul Lee ◽  
Yu-Chan Kim ◽  
E. Fleury ◽  
Jae-Chul Lee
Keyword(s):  
Amorphous Alloy ◽  
Amorphous Alloys ◽  
Glass Forming Ability ◽  
Bulk Amorphous Alloy ◽  
Mixing Enthalpy ◽  
High Plasticity ◽  
Atomic Packing ◽  
Bulk Amorphous Alloys ◽  
Glass Forming ◽  
Enthalpy Difference

We synthesized bulk amorphous alloy systems of Cu43Zr43Al7X7 (X = Be, Ag; numbers indicate at.%), with the objective of simultaneously enhancing the glass-forming ability (GFA) and the plasticity. The alloys not only exhibit high plasticity (∼7%, ∼8%), but also possess enhanced GFA (alloys with 12 and 8 mm diameter). The possible mechanisms underlying this enhanced GFA and plasticity exhibited by these alloys are discussed based on the atomic-packing state and atomistic-scale compositional separation associated with the mixing enthalpy difference. A strategy for designing bulk amorphous alloys with simultaneous improvement in the GFA and the plasticity is proposed from the viewpoint of atomic-packing state and atomistic-scale phase separation.

Critical Cooling Rate for the Glass Formation of Fe80-XCoxP13C7 Alloy

2013 ◽  
Vol 745-746 ◽  
pp. 799-808
Author(s):  
Kai Xu ◽  
Yan Wang ◽  
Qiang Li
Keyword(s):  
Amorphous Alloy ◽  
Cooling Rate ◽  
Thermodynamic Data ◽  
Glass Formation ◽  
Amorphous Alloys ◽  
Experimental Results ◽  
Bulk Amorphous Alloy ◽  
Cooling Rates ◽  
Critical Cooling Rate ◽  
Dta Curves

In this work, the critical cooling rate Rc for glass formation of a series of Fe80-xCoxP13C7 (x = 0, 5, 10, 15, 20 at.%) alloys was determined by means of constructing CCT curves using Uhlmanns method. The calculated critical cooling rates for x = 0, 5, 10, 15, 20 at.% are 621, 441, 548, 894, 922 K/s, respectively. These results well coincide with the maximum diameters of Fe80-xCoxP13C7 amorphous alloys determined by experiments varying with the content of Co. The calculated Rc was also on the reasonable order of magnitudes. In addition, the values of three common GFA criterions of Trg, ΔTx and γ were calculated according to the thermodynamic data determined from DSC and DTA curves of Fe80-xCoxP13C7 (x = 0, 5, 10, 15, 20 at.%) bulk amorphous alloy. The validity of these GFA criterions in the series of Fe80-xCoxP13C7 (x = 0, 5, 10, 15, 20 at.%) alloys were investigated and it was pointed out that these three GFA criterions were not able to explain the experimental results of the maximum diameters of Fe80-xCoxP13C7 amorphous alloys varying with the content x of Co.

Numerical Model of Thermal Field Developed in Fe67Cr4Mo4Ga4P12B5C4 Bulk Amorphous Alloy Processing

2016 ◽  
Vol 254 ◽  
pp. 249-254
Author(s):  
Bogdan Radu ◽  
Dragoş Buzdugan ◽  
Cosmin Codrean ◽  
Viorel Aurel Şerban ◽  
George Vișan
Keyword(s):  
Amorphous Alloy ◽  
Amorphous Alloys ◽  
Amorphous Materials ◽  
Thermal Field ◽  
Good Control ◽  
Experimental Tests ◽  
Glass Forming Ability ◽  
Bulk Amorphous Alloy ◽  
Bulk Amorphous Alloys ◽  
Glass Forming

Metallic amorphous materials were developed during 80’s as new materials, with very interesting industrial properties (heat conductivity, magnetic properties, fusion temperature, corrosion resistance, etc.). Technology to obtain these materials, based on very rapid cooling of a melted alloy with glass forming ability, has limitations for the dimensions of the products that can be obtained with amorphous structure (thickness has to be very thin), which can be overpassed by development of bulk amorphous alloys with high glass forming ability and good control of the cooling speed. Numerical modeling of thermal field during ultra-high cooling, developed in researches presented in this paper, allows researchers to estimate the results of applying in reality certain cooling conditions. This model will help developers of bulk amorphous alloys in checking if are ensured conditions to obtain an amorphous alloy with fewer experimental tests, less time and low expenses.

The forming and crystallization behaviors of Zr50Ti5Cu27Ni10Al8 bulk amorphous alloy by laser additive manufacturing

2020 ◽  
Vol 10 (7) ◽  
pp. 1155-1160 ◽  
Author(s):  
Yaqiong Ge ◽  
Xin Chen ◽  
Zexin Chang
Keyword(s):  
Amorphous Alloy ◽  
Cooling Rate ◽  
Heat Affected Zone ◽  
Molten Pool ◽  
Amorphous Structure ◽  
Bulk Amorphous Alloy ◽  
Preparation Process ◽  
Laser Additive Manufacturing ◽  
Obvious Effect ◽  
Composition And Structure

Due to the small size and serious crystallization, the wider application of amorphous alloy materials is limited. In this paper, the bulk amorphous alloy with the size of 15 mm × 15 mm × 12 mm was made by selective laser melting technology. The characters of the composition and structure of the as-prepared bulk amorphous alloy and the thermal effect of the preparation process were analyzed. The results showed that the cooling rate of both the molten pool and the heat affected zone were much higher than the critical cooling rate of the amorphous alloy and, therefore, the cooling rate was not the reason for the crystallization in this experiment. The molten pool of the formed amorphous alloy block was completely amorphous. Due to the accumulation of structural relaxation, crystallization occurred in the heat affected zone, but the amorphous structure was still dominant. The increase in deposition layer had no obvious effect on crystallization.

Effect of Neodymium on the Glass-Forming Ability and Magnetic Properties of Fe-Based Bulk Amorphous Alloys

2015 ◽  
Vol 1120-1121 ◽  
pp. 440-445
Author(s):  
Hua Man
Keyword(s):  
Magnetic Properties ◽  
Amorphous Alloys ◽  
Glass Forming Ability ◽  
High Thermal Stability ◽  
Bulk Amorphous Alloy ◽  
Soft Magnetic Properties ◽  
Soft Magnetic ◽  
Crystallization Peak ◽  
Bulk Amorphous Alloys ◽  
Glass Forming

The glass forming ability and magnetic properties were investigated for adding neodymium to the Fe71-xNb4B25Ndx (x=0, 3, 5, 7,10) alloys prepared by copper suction casting. It was found that proper neodymium (x=5~10 at.%) could improve glass forming ability of Fe-Nb-B alloys effectively. Bulk amorphous Fe66Nd5B25Nb4 and Fe64Nd7B25Nb4 samples were obtained and presented high thermal stability and good soft magnetic properties. The value of activation energy of the first crystallization peak for the bulk amorphous alloy Fe64Nd7B25Nb4 is 683 kJ/mol.

Design of the Components of the Fe-Based Bulk Amorphous Alloys

2012 ◽  
Vol 487 ◽  
pp. 453-456
Author(s):  
Yu Fang Yang ◽  
W. Gao ◽  
D.L. Yan
Keyword(s):  
Amorphous Alloy ◽  
Amorphous Alloys ◽  
Copper Mold ◽  
Bulk Amorphous Alloys ◽  
Copper Mold Casting ◽  
Mold Casting ◽  
The Cost

It’s well known that bulk Fe-based amorphous alloy is difficult to fabricate, but we develop low price Fe-based amorphous alloys applied in practice after systemic analyzing and considering the cost demand of the application. Finally, there are 7 Fe-based amorphous alloys fabricated by advanced copper mold casting after careful attempt.

scholarly journals Effect of Niobium and Yttrium Modified Ti-Based Bulk Amorphous Alloy on Correlation of Plastic Deformation Energy and Ductility

2019 ◽  
Author(s):  
Shengfeng Shan ◽  
Bing Zhang ◽  
Yuanzhi Jia ◽  
Mingzhen Ma
Keyword(s):  
Electron Microscopy ◽  
Plastic Deformation ◽  
Amorphous Alloys ◽  
Shear Bands ◽  
Deformation Energy ◽  
Bulk Amorphous Alloy ◽  
High Plasticity ◽  
Band Formation ◽  
Bulk Amorphous Alloys ◽  
Uniaxial Compressive Test

A series of Ti40Zr25Cu9Ni8Be18)100-xTMx (x = 0, 1, 2, 3, 4 at.%, TM = Nb, Y) Bulk amorphous alloys were designed and prepared using the copper mold casting method. The microstructures, glass forming ability and mechanical properties of the alloys were investigated by means of X-ray diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), differential scanning colorimetry (DSC), depth-sensitive nanoindentation and uniaxial compressive test. The Bulk amorphous alloys with different ductility were investigated by measuring their plastic deformation energy (PDE) of the first pop-in events during loading. The relationships between the PDE value, shear band formation and ductility in Bulk amorphous alloys have been investigated. The results show that the PDE value decreases by the Nb addition and promotes the generation of multiple shear bands easily, which increase the fracture strength and plasticity significantly. Substituting Nb with Y has exactly the reverse effect. A useful rule for preparing of Bulk amorphous alloys with high plasticity is herein proposed, whereby the chemical composition of the Bulk amorphous alloys can be tailored to possess a lower PDE value.

Critical Cooling Rate of Y36Nd20Al24Co20 Bulk Amorphous Alloy

2014 ◽  
Vol 670-671 ◽  
pp. 86-89
Author(s):  
Shi Wen He
Keyword(s):  
Glass Transition ◽  
Amorphous Alloy ◽  
Cooling Rate ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Glass Forming Ability ◽  
Bulk Amorphous Alloy ◽  
Liquid Region ◽  
Critical Cooling Rate ◽  
Glass Forming

A new bulk amorphous alloy, Y36Nd20Al24Co20, with a diameter of 5 mm was successfully fabricated by the method of equiatomic substitution for the Y element in Y56Al24Co20amorphous alloy. The values of the supercooled liquid region ∆Tx(=Tx-Tg), the reduced glass transition temperature Trg(=Tg/Tl) and the parameter γ (=Tx/(Tg+Tl)) for Y36Nd20Al24Co20bulk amorphous alloy are 60K, 0.605 and 0.415, respectively. The critical cooling rate of the Y36Nd20Al24Co20bulk amorphous alloy was determined to be 40 K/s, providing an indication that this alloy has a high glass-forming ability.

Effects of Cr or Mo Compositions on Mechanical Behavior of Fe-Base Bulk Amorphous Alloy

2015 ◽  
Vol 1110 ◽  
pp. 136-141 ◽  
Author(s):  
Beom Taek Jang ◽  
Young In Kim
Keyword(s):  
Amorphous Alloys ◽  
Wear Test ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Bulk Amorphous Alloy ◽  
Liquid Region ◽  
Wear Property ◽  
Casting Technique ◽  
Bulk Amorphous Alloys ◽  
Mo Content

For enhancing wear property of Fe-based bulk amorphous alloys as structural materials, We investigate effects of Cr or Mo compositions on wear and mechanical behaviors of FeCSiBPMo and FeCSiBPAlCr system bulk amorphous alloys which are suction-cast into a copper mold by arc melting in an argon atmosphere using a suction casting technique. X-ray diffraction, differential scanning calorimeter and Scanning electron microscopy were used to observe the microstructure and surface morphologies. Cr-Fe or Mo-Fe substitutions led to a dramatic increase in the glass transition temperature as well as the supercooled liquid region. After the wear test, the mass loss of both BAAs decreased remarkably at higher element. Nanoindentation results indicate that with an increase of the Cr or Mo compositions, the hardness and elastic modulus increased in both BAA samples. These results suggest that wear behaviors of the BAAs corresponded to change in hardness, which means that fracture morphologies of worn surface are strongly dependent on surface hardening with high Cr or Mo content.

Synthesis and Properties of Ferromagnetic Bulk Amorphous Alloys

1998 ◽  
Vol 554 ◽  
Author(s):  
A. Inoue ◽  
T. Zhang ◽  
H. Koshiba ◽  
T. Itoi
Keyword(s):  
Thermal Stability ◽  
Amorphous Alloy ◽  
Rapid Solidification ◽  
Amorphous Alloys ◽  
Supercooled Liquid ◽  
Soft Magnetic Materials ◽  
Bulk Amorphous Alloys ◽  
Application Fields ◽  
Ferromagnetic Bulk ◽  
Alloy Systems

Since an amorphous phase in Au-Si system was synthesized for the first time by rapid solidification in 1960[1], a large number of amorphous alloys have been prepared by various rapid solidification techniques. As the main amorphous alloy systems, one can list up the noble metal-, Fe-, Co-, Ni-, Ti-, Zr-, Nb-, Mo-, lanthanide(Ln)-, Al- and Mg-based alloys. Among these alloy systems, Fe-[2], Co-[2] and Al-[3]based amorphous alloys have been used in application fields of magnetic and high specific-strength materials. Thus, Fe- and Co-based amorphous alloys have gained the most important position as engineering amorphous alloys. When special attention is paid to Fe-based amorphous alloys, Fe-P-C alloys were synthesized in 1967[4] as the first Febased amorphous alloy. Subsequently, engineering important (Fe,Co)-Si-B amorphous alloys have been developed in 1974[5][6], followed by the formation of (Fe,Co,Ni)-(Cr,Mo,W)-C in 1978[7], (Fe,Co,Ni)-(Zr,Hf) in 1980[8] and then (Fe,Co,Ni)-(Zr,HfNb)-B amorphous alloys in 1981[9]. The (Fe,Co)-Si-B amorphous alloys have been used in many application fields as soft magnetic materials[2]. However, after 1981, nobody have succeeded in finding a new amorphous alloy in Fe- and Co-based systems by rapid solidification from liquid phase. Besides, all these amorphous alloys have serious disadvantages that high cooling rates above 105 K/s are required for glass formation and the resulting sample thickness is limited to less than about 50 μm[ 10]. Great efforts have been devoted to find Fe- and Co-based amorphous alloys with a high thermal stability of supercooled liquid against crystallization and a high glass-forming ability (GFA). Very recently, we have succeeded in finding new ferromagnetic bulk amorphous alloys with critical sample thicknesses ranging from I to 15 mm in Fe-(AI,Ga)-(P,C,B,Si)[11]-[14], (Fe,Co,Ni)-(Zr,IHf,Nb)- B[15]-[17], (Fe,Co)-(Zr,Hf)-(Nb,Ta)-(Mo,W)-B[18], (Fe,Co)-Ln-B[19] (Ln=lanthanide metal) and (Nd,Pr)-Fe-Al[20]-[22] systems. In this review, we present the formation, thermal stability, mechanical strength and magnetic properties of these new ferromagnetic bulk amorphous alloys.

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