The detrimental effect of flux-induced boron alloying in Pd–Si–Cu bulk metallic glasses

Abstract

We report on advanced insights into the fluxing of Pd–Si–Cu bulk metallic glasses. Flux-induced boron alloying and trapping of oxides are found to be associated with the employed boron oxide fluxing agent, and both influence the attainable glass-forming ability (GFA) in opposite ways. Incorporated boron strongly deteriorates the GFA due to a rising liquidus temperature, while the oxygen reduction improves it. Thus, proper fine-tuning of the fluxing time and overheating characteristics leads to an enhancement of GFA. In the current case, the critical diameter of Pd77.5Si16.5Cu6 bulk metallic glasses can be increased to 15 mm, as compared to 3 mm in the unfluxed case. Based on these results, we illustrate that the development of further fluxing agents is crucial for enhancement of the key properties of bulk metallic glasses.

On the understanding of the effects of sample size on the variability in fracture toughness of bulk metallic glasses

“…The cyclic heating-cooling treatment associated with fluxing was performed for eight fluxing cycles between 300°C and 1150°C with an overall fluxing time of 24 hours. A detailed description of the fluxing procedure is provided in our preceding publications[76,77].…”

Effectiveness of hydrogen microalloying in bulk metallic glass design

“…1a presents the XRD patterns of the Ar-cast and H 2 -alloyed Pd-Si-Cu rods of 2 mm diameter, which both appear to be amorphous. This finding is comprehensible because the diameter of the specimens prepared is slightly lower than the reported critical casting thickness [22]. Similarly, Fig.…”

Effect of copper addition on the glass forming ability in Pd-Si binary amorphous alloying system

“…Adding Cu to the system to form a Pd-Cu-Si ternary alloy, leads to a huge improvement of the critical diameter from 8mm to 15mm, 7,8 which confirmed the effective role of alloying method in improving the glass forming ability of metallic glasses. 9 Pd-Cu-Si, one of the first bulk metallic glasses developed in 1974 by Chen et al, was often selected for scientific investigation in the common composition Pd 77.5 Cu 6 Si 16.5 , 10-13 but systematic study on the effect of different Cu addition on the glass formation is still limited.…”

“…9 Pd-Cu-Si, one of the first bulk metallic glasses developed in 1974 by Chen et al, was often selected for scientific investigation in the common composition Pd 77.5 Cu 6 Si 16.5 , 10-13 but systematic study on the effect of different Cu addition on the glass formation is still limited. In this case, the binary alloy series Pd 81+x Si 19-x (x=0, 1, 1.5, 2, 2.5, 3, 4) and the ternary alloy series Pd 83.5-x Cu x Si 16.5 (x=0, 2,4,6,8,10,12) were selected to investigate the effect of Cu additions on the glass forming ability (GFA) and thermal stability in the binary Pd-Si system. First, a combination of X-ray diffraction (XRD), transmission electronic microscopy (TEM) and differential scanning calorimetry (DSC) was used to investigate the amorphous state of the produced samples.…”