https://dc.engconfintl.org/cgi/viewcontent.cgi?article=1032&context=superalloys_ii

A critical review of high entropy alloys and related concepts

Microstructures and properties of high-entropy alloys

Amorphous alloys were first developed over 40 years ago and found applications as magnetic core or reinforcement added to other materials. The scope of applications is limited due to the small thickness in the region of only tens of microns. The research effort in the past two decades, mainly pioneered by a Japanese- and a US-group of scientists, has substantially relaxed this size constrain. Some bulk metallic glasses can have tensile strength up to 3000 MPa with good corrosion resistance, reasonable toughness, low internal friction and good processability. Bulk metallic glasses are now being used in consumer electronic industries, sporting goods industries, etc. In this paper, the authors reviewed the recent development of new alloy systems of bulk metallic glasses. The properties and processing technologies relevant to the industrial applications of these alloys are also discussed here. The behaviors of bulk metallic glasses under extreme conditions such as high pressure and low temperature are especially addressed in this review. In order that the scope of applications can be broadened, the understanding of the glass-forming criteria is important for the design of new alloy systems and also the processing techniques.

https://www.tcd.ie/Physics/people/Graham.Cross/SF%20Poster%202011/Shek-MaterSciEng04-Bulk%20Metallic%20Glasses.pdf

Bulk metallic glasses

https://www.tcd.ie/Physics/people/Graham.Cross/SF%20Poster%202011/Schuh-ActaMater07-Mechanical%20behaviour%20of%20amorphous%20alloys.pdf

Mechanical behavior of amorphous alloys

https://zenodo.org/record/1258680/files/article.pdf

The influences of temperature and microstructure on the tensile properties of a CoCrFeMnNi high-entropy alloy

We studied the E – J characteristics of a melt-textured YBa 2 Cu 3 O 7− δ sample by measuring its sweeping rate dependence of magnetization with a vibrating sample magnetometer Firstly, we derived the relationship between the electric field and sweeping rates from flux conservation equation, and furthermore developed a method of obtaining ln E –ln J curves and thermal excitation potential U 0 ( T , B ) from magnetization measurement Then, curves of ln E –ln J and U 0 ( T , B ) were deduced from the magnetic measurements on a melt-textured YBa 2 Cu 3 O 7− δ sample prepared by MTG method, and thereby different dynamic behaviors were studied in accordance with our experimental data

Investigating E–J characteristics of melt-textured YBa2Cu3O7−δ

Simultaneously increasing mechanical and corrosion properties in CoCrFeNiCu high entropy alloy via friction stir processing with an improved hemispherical convex tool

One of the major challenges in welding the Cu–Cr–Zr alloys is that the high welding temperature often causes the coarsening of the precipitates, resulting in lower joint strength. Various strategies were studied to reduce the welding temperature below the aging temperature for limiting the precipitate coarsening. The results showed that great challenges existed in reducing the friction stir welding (FSW) temperature below the peak-aging temperature of Cu–Cr–Zr alloy (420–480 °C) without using coolant. Through softening the Cu–Cr–Zr alloys to the supersaturated solid solution state prior to FSW, the peak temperature during FSW of Cu–Cr–Zr alloy under water was reduced to ∼481 °C, which is close to the aging temperate of the Cu–Cr–Zr alloy. After post-weld aging heat treatment, the stir zone exhibited higher hardness than the peak-aged Cu–Cr–Zr alloy due to the combination of the high density of precipitates 10.5 nm in diameter and refined grains 0.65 μm in diameter, enabling the achievement of high joint strength equal to the peak-aged base metal. In addition, the FSW zone also exhibited a high electrical conductivity of 88.9% IACS, which is higher than that of the peak-aged base material (81.0% IACS). 

Influence of processing innovations on joint strength improvements in friction stir welded high strength copper alloys

The performance of building-integrated photovoltaics (BIPV) shows high variations due to several factors, including design model uncertainty, installation mode, dirt/soil effects, aging factors, and manufacturing issues. This paper explores the uncertainty of BIPV outputs from the perspectives of both model uncertainty and parameter uncertainty using the EnergyPlus program. The sampling-based Monte Carlo method is implemented to conduct the uncertainty analysis of BIPV outputs. The meta-model global sensitivity analysis (Bayesian adaptive spline surfaces) is used to obtain important factors affecting BIPV outputs due to its high computational efficiency. The results indicate that both model and parameter uncertainty has significant influences on PV outputs. The combined remaining effect, power rating, and model uncertainty are three important factors influencing PV electricity. Therefore, these factors should be carefully chosen or adjusted to provide a reliable estimation of PV outputs.

/pdf/uncertainty-and-sensitivity-analysis-of-building-integrated-29ogd1c9.pdf

Uncertainty and Sensitivity Analysis of Building Integrated Photovoltaics

Na-doped YBa 1.9 Na 0.1 Cu 3 O y +40 mol%Y211 (YBNCO) and Na-free YBa 2 Cu 3 O y (YBCO) samples were fabricated by the melt-textured growth (MTG) method to study the effect of doped Na ion on flux pinning. The effective pinning energy ( U ( T , H dc , J )), irreversibility line ( H irr ( T )) and critical current density ( j c ( H dc )), were determined by measurement of ac susceptibility (acs) as well as hysteresis loop measurements for the samples, where T , H dc and J are temperature, dc magnetic field and current density, respectively. It is found that H irr ( T ) was shifted to lower temperatures while J c ( H dc ) and U ( T , H dc , J ) of YBNCO became smaller than that of YBCO. Hence, the doping Na ion plays a negative rule on enhancing flux pinning in YBCO. The appearance of the second peak in J c ( H dc ) relation and the enhancement of anisotropy in YBNCO is a further support to the conclusion.

H.F. Zhang

Papers

Investigating E–J characteristics of melt-textured YBa2Cu3O7−δ

Simultaneously increasing mechanical and corrosion properties in CoCrFeNiCu high entropy alloy via friction stir processing with an improved hemispherical convex tool

Influence of processing innovations on joint strength improvements in friction stir welded high strength copper alloys

Uncertainty and Sensitivity Analysis of Building Integrated Photovoltaics

Flux pinning energy of YBa1.9Na0.1Cu3O7−δ