Effects of Thermal Exposure and Test Temperature on Structure Evolution and Hardness/Viscosity of an Iron-Based Metallic Glass

Abstract

High-temperature microhardness testing on drop-cast ingots of fully amorphous Fe 48 Mo 14-Cr 15 Y 2 C 15 B 6 was performed in order to determine the behavior and structure evolution of this Fe-bulk metallic glass under a variety of different test conditions. The effects of changes in test temperature on the microhardness/strength were determined over the temperature range from room temperature to 620°C. Although high (e.g., >12 GPa) microhardness was exhibited at room temperature, significant hardness reductions were exhibited near T g . In addition, the effect of exposure time (up to 300 minutes) at elevated temperature on the evolution of microhardness/strength was also evaluated for selected temperatures between 25°C and 620°C. The microhardness results were complemented with X-ray diffraction (XRD), conventional transmission electron microscopy (TEM), and an in-situ heating TEM study in order to evaluate any structural evolution that could explain the large differences in hardness evolution under different test conditions.

Experimental Investigation and Numerical Simulation for Corrosion Rate of Amorphous/Nano-Crystalline Coating Influenced by Temperatures

“…Fe-based bulk metallic glasses (BMGs) have received significant interest in recent decades because of their superior performance, such as their high strength and hardness, good magnetic properties, and excellent corrosion and wear-resistance [1][2][3][4][5][6][7][8][9]. Compared to stainless steel and crystalline alloys with a similar composition, BMG boasts a uniform microstructure without any crystal imperfections, dislocations, or grain limits.…”

The Wear Resistance of HVOF Sprayed Composite Coatings

“…Composite coatings, which may have protective, technical, or decorative functions, are frequently deposited by using the thermal spraying process [1][2][3][4][5]. Advancements in spraying equipment have enabled application of new materials with better parameters.…”

“…High-velocity oxygen-fuel (HVOF) sprayed coatings are produced from powder materials [2,3]. They include hard alloys of Ni, Co, or Fe with Cr, B, and Si; Ti, Zr, and Hf carbides; V and Nb nitrides; and Cr, Mo, and W borides.…”

Shock Wave Response of Iron-based In Situ Metallic Glass Matrix Composites

“…Iron-based bulk metallic glasses (BMG), or amorphous steels, are known to have high hardness, high fracture strengths of 4 GPa or more, good corrosion resistance and magnetic properties, as well as the added advantage of lower material costs over other metallic glasses 1 2 3 4 5 6 . Even though Fe-BMGs have several attractive attributes, most of them have low toughness and are consequently extremely brittle and undergo catastrophic failure 1 , which severely limits their applications.…”

“…In order to ensure the viability of amorphous steels for use in structural applications, it is necessary to characterize their mechanical response over a wide range of strain rates. Thus far, there have been several studies on the quasi-static mechanical response of amorphous steels and their composites 1 6 9 10 11 16 , however, to the best of our knowledge, their high strain-rate shock wave response has not been explored yet. High strain-rate mechanical response is relevant for applications such as kinetic energy penetrators, ballistic armor, and satellite shields for protection from meteorite impact.…”