Relation of the fragility and heat capacity jump in the supercooled liquid region with the shear modulus relaxation in metallic glasses

Author(s):  
Andrey Makarov ◽  
Jichao Qiao ◽  
Nikolai Kobelev ◽  
Alexander S Aronin ◽  
Vitaly A Khonik
Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 929
Author(s):  
Dandan Liang ◽  
Jo-Chi Tseng ◽  
Xiaodi Liu ◽  
Yuanfei Cai ◽  
Gang Xu ◽  
...  

This study investigated the structural heterogeneity, mechanical property, electrochemical behavior, and passive film characteristics of Fe–Cr–Mo–W–C–B–Y metallic glasses (MGs), which were modified through annealing at different temperatures. Results showed that annealing MGs below the glass transition temperature enhanced corrosion resistance in HCl solution owing to a highly protective passive film formed, originating from the decreased free volume and the shrinkage of the first coordination shell, which was found by pair distribution function analysis. In contrast, the enlarged first coordination shell and nanoscale crystal-like clusters were identified for MGs annealed in the supercooled liquid region, which led to a destabilized passive film and thereby deteriorated corrosion resistance. This finding reveals the crucial role of structural heterogeneity in tuning the corrosion performance of MGs.


2008 ◽  
Vol 498 (1-2) ◽  
pp. 464-467 ◽  
Author(s):  
K.Q. Qiu ◽  
J. Pang ◽  
Y.L. Ren ◽  
H.B. Zhang ◽  
C.L. Ma ◽  
...  

2004 ◽  
Vol 19 (2) ◽  
pp. 427-428 ◽  
Author(s):  
Z.P. Lu ◽  
C.T. Liu

A new Mg-based bulk amorphous alloy (i.e., Mg65Cu25Gd10) has successfully been developed by Men and Kim [H. Men and D.H. Kim, J. Mater. Res. 18, 1502 (2003)]. They showed that this alloy exhibits significantly improved glass-forming ability (GFA) in comparison with Mg65Cu25Y10 alloy. However, this improved GFA cannot be indicated by the supercooled liquid region ΔT and the reduced glass-transition temperature Trg. As shown in the current comment, the new parameter γ, Tx/(Tg + Tl) defined in our recent papers [Z.P. Lu and C.T. Liu, Acta Mater. 50, 3501 (2002); Z.P. Lu and C.T. Liu, Phys. Rev. Lett. 91, 115505 (2003)] can well gauge GFA for bulk metallic glasses, including the current Mg-based alloys.


2009 ◽  
Vol 24 (2) ◽  
pp. 316-323 ◽  
Author(s):  
C.L. Qin ◽  
W. Zhang ◽  
K. Asami ◽  
N. Ohtsu ◽  
A. Inoue

Bulk metallic glasses (BMGs) with high thermal stability and good corrosion resistance were synthesized in the (Cu0.6Hf0.25Ti0.15)100−x−yNiyNbx system by copper mold casting. The addition of Ni element causes an extension of a supercooled liquid region (ΔTx = Tx – Tg) from 60 K for Cu60Hf25Ti15 to 70 K for (Cu0.6Hf0.25Ti0.15)95Ni5. The simultaneous addition of Ni and Nb to the alloy is effective in improving synergistically the corrosion resistance in 1 N HCl, 3 mass% NaCl, and 1 N H2SO4 + 0.01 N NaCl solutions. The highly protective Hf-, Ti-, and Nb-enriched surface film is formed by the rapid initial preferential dissolution of Cu and Ni, which is responsible for the high corrosion resistance of the alloys in the solutions examined.


2021 ◽  
Vol 8 ◽  
Author(s):  
Xiong Liang ◽  
Caitao Fan ◽  
Jianan Fu ◽  
Zehang Liu ◽  
Zhenxuan Zhang ◽  
...  

In this work, a rapid and controllable ultrasonic vibration method for forming Al-based metallic glass at room temperature is proposed. This method can dramatically improve the forming ability of Al-based metallic glasses, which are virtually brittle at room temperature and have almost no supercooled liquid region at high temperatures. Under ultrasonic vibration, Al-based metallic glasses exhibited obvious plastic flow, with a maximum deformation degree up to 58% and an average deformation degree up to 43%. It is worth mentioning that no crystalline peaks were found on the X-ray diffraction patterns after deformation under ultrasonic vibration, and the mechanical properties remained the same as the primary sample. The present results provide a new approach for the deformation and forming of Al-based metallic glasses, which can significantly broaden their applications.


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