Recent development of chemically complex metallic glasses: from accelerated compositional design, additive manufacturing to novel applications

Abstract

Metallic glasses or amorphous alloys are an important engineering material that has a history of research of about 80-90 years. While different fast cooling methods were developed for multi-component metallic glasses between 1960s and 1980s, 1990s witnessed a surge of research interest in the development of bulk metallic glasses. Since then, one central theme of research in the metallic-glass community has been compositional design that aims to search for metallic glasses with a better glass forming ability, a larger size and/or more interesting properties, which can hence meet the demands from more important applications. In this review article, we focus on the recent development of chemically complex metallic glasses, such as high entropy metallic glasses, with new tools that were not available or mature yet until recently, such as the state-of-the-art additive manufacturing technologies, high throughput materials design techniques and the methods for big data analyses (e.g. machine learning and artificial intelligence). We also discuss the recent use of metallic glasses in a variety of novel and important applications, from personal healthcare, electric energy transfer to nuclear energy that plays a pivotal role in the battle against global warming.

A generative deep learning framework for inverse design of compositionally complex bulk metallic glasses

“…Here, we emphasize that, despite the dedicated efforts of over 60 years, the total number of the reported BMG compositions is only about 300 for the four types of BMGs (see Supplementary Table 1), implicative of the grand challenges facing the field as discussed in refs. 15,23 . To gauge data diversity, we carried out anatomic analyses of the compositional data with the hierarchical clustering method 45 (see "Methods").…”

“…In principle, GFA correlates positively with the maximum size that a glass-forming alloy can be cast into without crystallization, and therefore a superior GFA usually manifests as the successful casting of bulk metallic glasses (BMGs) with a typical size >1 mm 13 . Nevertheless, according to the literature 15 , only 10% of the reported glass-forming alloys can form BMGs despite the tremendous efforts paid for over the past decades. By tradition, the discovery of a BMG composition was usually based on a trial-and-error iterative approach that encompassed empirical rules 16 , such as the eutectic point rule 17 , the confusion principle 18 , and others 19 .…”

“…29 . Although this supervised learning approach has been proven useful 25,27,30 , however, it quickly runs into a bottleneck with the increasing compositional complexity of alloys, such as high entropy metallic glasses 15,31 that contain more than five principal elements. In such a case, sampling the compositional space, which contains an astronomical number of candidate alloys 32 , through supervised learning becomes impractical, if not impossible, in order to identify only a few BMG compositions out of millions or even more human-guided inputs.…”

Inheritance factor on the physical properties in metallic glasses

“…As one of the important systems in condensed matter physics and material science, metallic glasses (MGs) have attracted intense attention over the past decades owing to their distinctive properties, e.g. high strength, good corrosion resistance, and excellent soft magnetic properties [1]. Since their discovery in 1960 [2], thousands of MG compositions have been developed based on a wide range of elements [3].…”

Unusual effect of high pressures on phase transformations in Ni62Nb38 alloy

“…In addition, the liquidus line T l (p) and the glass transition line T g (p) were still unknown for this system. The dependencies T l (p) and T g (p) are difficult to determine experimentally because of problems with the realization of cooling and heating protocols at high pressures [19]. Therefore, there are still no experimental data to construct the detailed (p, T ) phase diagram of binary Ni 62 Nb 38 alloy.…”