Progress in the preparation, forming and machining of metallic glasses

Xiaoke Li, Gaohui Li, Jun Ma, Yang Cao, Yapeng Xu, Wuyi MingShow moreAdd to MendeleyShareCite rights and content


  • •The latest development of preparation, forming and processing of MGs is reviewed.
  • •The breakthroughs and limitations of the latest research are summarized.
  • •Analyze the crystallization and other characteristics of each process.
  • •The pros and cons of various processes for green manufacturing are compared.


Metallic glasses (MGs), also known as amorphous alloys, has a unique atomic structure with long-range disorder and short-range order. MGs has excellent mechanical properties and is favored by many industries, such as, aerospace, medical devices, electronics and electricity, sports and leisure, etc. However, large-size MGs is hardly prepared in engineering due to the limited glass-forming ability (GFA). Moreover, the high hardness and low plasticity of MGs make the forming and machining difficult, which hindered its widespread application. Therefore, many researchers have focused on improving the preparation, forming, and machining ability of MGs. In this paper, the latest developments on preparation and machining are summarized, and a comprehensive review of MGs forming was firstly conducted. Then, the crystallization, MGs size range, surface roughness of different processes are discussed statistically. Finally, future research for the preparation, forming, and machining of MGs are discussed and prospected, and other research hotspots are analyzed. Furthermore, with the gradual maturity of MGs production technology, the importance of green manufacturing for sustainable development is emphasized, and several suggestions are put forward.


Compared with traditional crystalline alloys, metallic glasses (MGs), also called as amorphous alloys, has superior properties such as high strength, high hardness, large elastic strain limit, large allowable damage limit, high corrosion resistance, and excellent magnetic, catalytic, and superconducting properties [1], [2], [3], [4]. Therefore, MGs has gradually become the research hotspot in fields such as aerospace, micro-electro-mechanical systems(MEMS), biomedical, electronics and power, advanced infrastructure, sports and leisure, jewelry industry, luxury goods, etc. [5], [6], [7], [8]. Fig. 1 shows the comparison of atomic structures of MGs and crystalline alloys, as well as a simple schematic diagram of the transformation from MGs to grain boundary. Unlike traditional crystalline alloys with periodic and regular arrayed atoms, MGs atoms exhibit long-range disorder and short-range order characteristics, thus they have no crystallographic defects such as grain boundaries, vacancies, and dislocations, making it possess metallic, amorphous, and liquid-like properties [5], [9], [10], [11].

In 1960, Klement et al. [12] first produced the metal-silicon alloys, which is now known as the MGs, using the gas-phase deposition method. Then, Thamburaja and Ekambaram [13] developed the limited deformation and thermo-mechanical coupling theories for MGs, which accurately predicted the steady-state stress and free volume concentration data for different strain rates during simple tension. Li et al. [14] successfully prepared a series of porous bulk metallic glass foams with porosities ranging from 46% to 75% using the space holder technique, which are in good agreement with the modulus and yield strength of human bone and with the predicted values of theoretical models. Li et al. [15] successfully prepared large bulk metallic glass composites (BMGCs) without cracks using the selective laser melting of Al85Ni5Y65Co2Fe2. Based on the geometric and energetic characteristics of crystalline phases calculated from first principles using the Automatic flow (Aflow) framework, Eric et al. [16] developed the robust model to predict the glass-forming ability (GFA), showing that more than 17% of binary alloy systems could form glasses.

However, the application of MGs is relatively rare, the main reasons are as follows: MGs preparation is limited by the GFA and maximum cooling rate of the alloys (generally in the range of 100 ∼103 K/s [17]), and there is a maximum critical casting diameter in MGs preparation, which limits the size of the castings [18], [19]. In practical applications, MGs has poor plasticity at room temperature and cannot undergo larger plastic deformation, resulting in unexpected fracture of MGs components [20]. Additionally, the brittleness, poor deformation ability, and low thermal conductivity, making MGs difficult to process. Traditional mechanical machining can lead to adverse issues such as high luminosity, oxidation, crystallization, and burrs, making it difficult to produce high-precision parts with the original mechanical properties [5], [21]. Furthermore, MGs is difficult to maintain long-term stability and has high preparation and processing costs, which also affects its application.

In recent years, with the continuous exploration of MGs, new technologies have been developed. For example, additive manufacturing can surpass the upper limit of the cooling rate (up to 103∼108 K/s) of traditional preparation methods, breaking through the size limitation of MGs [22], [23]; hot forming, cold rolling, and severe plastic deformation (SPD) processes can improve the plasticity of MGs [24], [25]; high-quality MGs parts can be produced by optimizing process parameters and improving external conditions, and the emergence of non-traditional machining methods bring more possibilities for the processing of MGs [26], [27]. Therefore, this paper summarizes the recent advances in preparation and machining technologies, and also provides a systematic summary of the forming of MGs firstly. The characteristics of these technologies are reviewed and compared, and an attempt is made to present the limitations of these processes. The characteristics and challenges of the processes of preparation, forming, and machining of MGs are discussed, and future research are envisioned with respect to these challenges. Finally, the importance of green manufacturing is proposed, the influence of different processes green manufacturing are analyzed, and several suggestions for the future development of green manufacturing are put forward. The flow chart of this paper is shown in Fig. 2 [24], [28], [29], [30], [31], [32], [33], [34], [35], [36], [37], [38], [39], [40].