Establishing the Glass Forming Ability of Ferromagnetic Bulk Amorphous Alloys Using a Mathematical Model Based on the Chemical Composition

2012 ◽  
Vol 188 ◽  
pp. 11-14
Author(s):  
Dragoş Buzdugan ◽  
Cosmin Codrean ◽  
Mircea Vodǎ ◽  
Viorel Aurel Şerban
Keyword(s):  
Mathematical Model ◽  
Chemical Composition ◽  
Amorphous Alloys ◽  
Primary Crystallization ◽  
Glass Forming Ability ◽  
Bulk Amorphous Alloys ◽  
Glass Forming ◽  
Ferromagnetic Alloys ◽  
The Difference ◽  
Ferromagnetic Bulk

This paper presents a mathematical model that describes the influence of the chemical composition on the glass forming ability of ferromagnetic alloys. Glass forming ability is given by the difference between the glass transition temperature and the primary crystallization temperature of the alloy. The glass forming ability is better as long this difference has a higher value. These temperatures were determined using differential thermal analysis.

scholarly journals Survey of BGFA Criteria for the Cu-Based Bulk Amorphous Alloys

2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
D. Janovszky ◽  
K. Tomolya ◽  
M. Sveda ◽  
A. Roosz
Keyword(s):  
Amorphous Alloys ◽  
Critical Thickness ◽  
Glass Forming Ability ◽  
Bulk Glass ◽  
The Real ◽  
Bulk Amorphous Alloys ◽  
Glass Forming ◽  
Versus Plot ◽  
Mismatch Condition

To verify the effect of composition on the bulk glass forming ability (BGFA) of Cu-based alloys, properties have been collected from the literature (~100 papers, more than 200 alloys). Surveying the BGFA criteria published so far, it has been found that the atomic mismatch condition of Egami-Waseda is fulfilled for all the Cu-based BGFAs, the value being above 0,3. The Zhang Bangwei criterion could be applied for the binary Cu-based alloys. The Miracle and Senkov criteria do not necessarily apply for Cu based bulk amorphous alloys. The critical thickness versus plot of Lu and Liu extrapolates to , somewhat higher than the 0.33 value found in other BGFA alloys. The Park and Kim parameter correlates rather poorly with the critical thickness for Cu based alloys. The Cheney and Vecchino parameter is a good indicator to find the best glass former if it is possible to calculate the exact liquids projection. In 2009 Xiu-lin and Pan defined a new parameter which correlates a bit better with the critical thickness. Based on this survey it is still very difficult to find one parameter in order to characterize the real GFA without an unrealized mechanism of crystallization.

Crystallization of Ni-Cr-Si-B and Ni-Cr-Fe-Si-B Amorphous Alloys

2014 ◽  
Vol 216 ◽  
pp. 35-38 ◽  
Author(s):  
Cosmin Codrean ◽  
Dragoş Buzdugan ◽  
Ramona Lǎzar ◽  
Viorel Aurel Şerban ◽  
Ion Mitelea
Keyword(s):  
Thermal Stability ◽  
Chemical Composition ◽  
Rapid Solidification ◽  
Amorphous Alloys ◽  
Structural Characteristics ◽  
Glass Forming Ability ◽  
Glass Forming ◽  
Melting Temperatures ◽  
Dta Analysis ◽  
Thermal Stability Of

Ni based amorphous alloys with Si and B, which can also, contains Fe and Cr, prepared by rapid solidification, have low melting temperatures. This fact increases their susceptibility to be joined by welding and brazing. The glass forming ability (GFA) is conditioned also by the crystallization delay, due to certain chemical composition of the alloys. The thermal stability of these alloys was revealed by DTA analysis and structural characteristics were investigated by XRD. Applying an annealing at temperatures between 420°C and 540°C, with 30 minutes maintaining time, allowed the investigation of phase occurred during the crystallization and the estimation of the crystalline grains dimensions.

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.

Mg–Ca–Zn Bulk Metallic Glasses with High Strength and Significant Ductility

2005 ◽  
Vol 20 (8) ◽  
pp. 1935-1938 ◽  
Author(s):  
X. Gu ◽  
G.J. Shiflet ◽  
F.Q. Guo ◽  
S.J. Poon
Keyword(s):  
Metallic Glasses ◽  
Amorphous Alloys ◽  
Mass Density ◽  
High Strength ◽  
Light Metal ◽  
Glass Forming Ability ◽  
Bulk Glass ◽  
Bulk Amorphous Alloys ◽  
Specific Strength ◽  
Glass Forming

The development of Mg–Ca–Zn metallic glasses with improved bulk glass forming ability, high strength, and significant ductility is reported. A typical size of at least 3–4 mm amorphous samples can be prepared using conventional casting techniques. By varying the composition, the mass density of these light metal based bulk amorphous alloys ranges from 2.0 to 3.0 g/cm3. The typical measured microhardness is 2.16 GPa, corresponding to a fracture strength of about 700 MPa and specific strength of around 250–300 MPa cm3/g. Unlike other Mg- or Ca-based metallic glasses, the present Mg–Ca–Zn amorphous alloys show significant ductility.

Predicted Optimum Composition for the Glass-Forming Ability of Bulk Amorphous Alloys: Application to Cu–Zr–Al

2012 ◽  
Vol 3 (21) ◽  
pp. 3143-3148 ◽  
Author(s):  
Qi An ◽  
Konrad Samwer ◽  
William A. Goddard ◽  
William L. Johnson ◽  
Andres Jaramillo-Botero ◽  
...  
Keyword(s):  
Amorphous Alloys ◽  
Glass Forming Ability ◽  
Optimum Composition ◽  
Bulk Amorphous Alloys ◽  
Glass Forming

Bulk Glass Formation in an Fe-Based Fe–Y–Zr–M (M = Cr, Co, Al)–Mo–B System

2004 ◽  
Vol 19 (3) ◽  
pp. 921-929 ◽  
Author(s):  
Z.P. Lu ◽  
C.T. Liu ◽  
C.A. Carmichael ◽  
W.D. Porter ◽  
S.C. Deevi
Keyword(s):  
Metallic Glasses ◽  
Glass Formation ◽  
Amorphous Alloys ◽  
High Strength ◽  
Supercooled Liquid ◽  
Glass Forming Ability ◽  
Bulk Glass ◽  
Bulk Amorphous Alloys ◽  
Glass Forming ◽  
Hardness Values

Several new bulk metallic glasses based on Fe–Y–Zr–(Co, Cr, Al)–Mo–B, which have a glass-forming ability superior to the best composition Fe61Zr10Co7Mo5W2B15 reported recently, have been successfully developed. The as-cast bulk amorphous alloys showed a distinctly high thermal stability with glass-transition temperatures above 900 K, supercooled liquid regions above 60 K, and high strength with Vickers hardness values larger than HV 1200. The suppression of the growth of primary phases in the molten liquids and the resultant low liquidus temperatures were found to be responsible for the superior glass-forming ability in these new alloys. It was found that the addition of 2% Y not only facilitated bulk glass formation, but the neutralizing effect of Y with oxygen in the molten liquids also improved the manufacturability of these amorphous alloys.

Effect of yttrium on the glass-forming ability of Fe–Cr–Mo–C–B bulk amorphous alloys

2007 ◽  
Vol 427 (1-2) ◽  
pp. 190-193 ◽  
Author(s):  
Qingjun Chen ◽  
Deliang Zhang ◽  
Jun Shen ◽  
Hongbo Fan ◽  
Jianfei Sun
Keyword(s):  
Amorphous Alloys ◽  
Glass Forming Ability ◽  
Bulk Amorphous Alloys ◽  
Glass Forming

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.

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