Preparation, Magnetic and Mechanical Properties of Fe/Ni-Based Amorphous Fibers.

In this study, we successfully fabricated Fe61Zr10Co5Mo7W2B15 and Ni61Nb19.2Ta19.8 amorphous fibers (AFs) using the melt-extraction method. This method ensured a rapid cooling, uniform quality, minimal defects, and superior performance. Magnetic property analysis revealed that the Fe-based AFs exhibited a single-slope magnetization curve characteristic of paramagnetic or diamagnetic materials, while the Ni-based AFs displayed a rectangular curve with low magnetic hysteresis, typical of ferromagnetic materials. The axial saturation magnetization of as-prepared Ni-based AFs is ~1.5 × 10-7 emu/g, with a coercivity of about 85 Oe. The statistical analysis of tensile tests indicated that Ni-based AFs possess a higher fracture threshold of 2440 ± 199 MPa and a reliability of 14.7, demonstrating greater material safety and suitability for high-performance applications. As opposed to Ni-based AFs, Fe-based AFs present a fracture threshold and of 1582 ± 692 MPa and a reliability 4.2. Moreover, under cyclic loading conditions, Ni-based AFs exhibited less residual deformation and superior elastic recovery with a fracture strength of 2800 MPa. These findings highlight the potential of Ni-based AFs for advanced engineering applications, particularly where high strength, durability, and excellent magnetic properties are required, paving the way for their integration into next-generation technologies.

Intermediate-Temperature Tensile Behavior of a Hot-Rolled Mg-Li-Al-Cd-Zn Alloy.

Developing light structure materials that work stably at elevated temperatures is a long-standing challenge for many application fields, particularly in the development of aerospace equipment. Zn/Cd alloying elements were prospected to improve the stability of the lightest Mg-Li based alloys; however, little is known about the intermediate-temperature mechanical properties of such alloys. The present work investigated the tensile behaviors of a cold-rolled Mg-Li-Al-Cd-Zn alloy in a temperature range of 30-150 °C. The results indicate that the alloy can host a tensile strength σUTS of 108~121 MPa, a yield strength σYP of 97~109 MPa and elongation εB of 14-15 % at 150 °C, dependent on the tensile direction. The mechanical properties intensively are modulated by temperature through the competition between work hardening and softening. Work hardening due to dislocation blocking by the precipitated MgLi2X phase dominated the deformation at low temperatures, while softening that resulted from dynamic recrystallization was the main effect at high temperatures. Correspondingly, a quasi-cleavage mechanism dominated the fracture at temperatures near room temperature, and microvoid coalescence worked at high temperatures above 100 °C. Our results offer a new experimental understanding of the elevated-temperature mechanical behaviors of Mg-Li alloys and will advance the development of new light magnesium alloys with high stability.

Liquid-solid joining of bulk metallic glasses.

Here, we successfully welded two bulk metallic glass (BMG) materials, Zr51Ti5Ni10Cu25Al9 and Zr50.7Cu28Ni9Al12.3 (at. %), using a liquid-solid joining process. An atomic-scale metallurgical bonding between two BMGs can be achieved. The interface has a transition layer of ~50 µm thick. The liquid-solid joining of BMGs can shed more insights on overcoming their size limitation resulting from their limited glass-forming ability and then promoting their applications in structural components.