Fe-based bulk metallic glasses: Glass formation, fabrication, properties and applications

Fe-based alloy material is widely used in the corrosive environment of seawater. It is replacing expensive cobalt and nickel-based alloys. Amorphous iron-based (Fe-based) alloy coatings can be deposited on stainless steel by high-velocity oxygen fuel (HVOF) thermal spraying. Following spraying, coatings were heat-treated at 500, 600, 700, 800, and 900 °C for up to three hours in a vacuum furnace. The microstructures of such coatings were analyzed herein using an optical microscope (OM) and scanning electron microscope (SEM) to monitor the morphologies of both powders and coatings of Fe-based alloy. Phase analysis was performed by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The goal of this work on the modification of Fe-based alloy feedstock powder is to enhance the corrosion and wear properties of these coatings. The results of this investigation reveal that adding a cobalt material to Fe-based alloy yields coatings with enhanced corrosion and tribological characteristics.

Enhancement of wear and corrosion resistance of iron-based hard coatings deposited by high-velocity oxygen fuel (HVOF) thermal spraying

The application of bulk metallic glasses (BMGs) as advanced wear-resistant materials has remained limited despite optimistic expectations. In this work, we develop a series of novel Fe-based BMGs with improved wear resistance by altering the Cr and Mo contents in an Fe–Cr–Mo–C–B–Y glass-forming system. Experimental results demonstrate that increasing Cr and Mo contents enhance the thermal stability and hardness (Hv) of the resulting BMGs without reducing their fracture toughness (Kc). The enhanced hardness is mainly attributed to the increased fraction of the stiff (Cr,Mo)–C covalent bonds in the resultant BMGs, as revealed by X-ray photoelectron spectrograph measurement. Worn surface/subsurface observations and stress field modeling reveal the activity of two kinds of wear mechanisms, i.e., hardness-controlled abrasion wear and toughness-controlled fatigue wear. We further clarify the enhanced wear performance of the Fe-based BMGs according to an effective indicator Kc3/4Hv1/2 that correlates positively ...

Design of Fe-Based Bulk Metallic Glasses with Improved Wear Resistance

Sliding wear behavior of Fe50−xCr15Mo14C15B6Erx (x=0, 1, 2 at%) bulk metallic glass

Electronic-structure origin of the glass-forming ability and magnetic properties in Fe–RE–B–Nb bulk metallic glasses

Fe(65−x)Mo14C15B6Erx bulk metallic glasses have been investigated by means of photoelectron spectroscopy. In order to obtain a clean surface the samples were fractured and analyzed in vacuum. The impact of the incorporation of Er on the local atomic structure, the bonding, and the valence band density of states was examined. Our results show that Er addition modifies the B–C bonding environment, which is expressed in the appearance of an additional peak in the C 1s core level. It also affects the Fe 3s multiplet splitting, indicating changes in the valence band electronic configuration. The change in the electronic structure is corroborated by examination of x-ray photoelectron spectroscopy (XPS) valence band spectra.

Influence of erbium on the electronic structure of Fe(65−x)Mo14C15B6Erx(x=0,1,2) bulk metallic glasses

Bulk metallic glasses consisting of Fe, Mo, Cr, C, B, and Er have been investigated by x-ray photoelectron spectroscopy, aimed to elucidate the local atomic structure of the amorphous phase In order to examine the electronic properties of this class of material, photon energy dependent measurements in combination with argon-ion irradiation were employed to identify and separate surface and bulk contributions to the spectra The core levels suggest the presence of a carbon-rich surface layer with oxidized boron and metals, and metal carbides and borides in the bulk Exposure to molecular oxygen and annealing experiments probe the chemical reactivity of the material Formation of boron oxides at comparably low temperatures (300°C) might have consequences for the stability of the amorphous phase We observe variations in binding energy of the Fe 3p core level with respect to the alloy composition, which indicate changes in the chemical state of iron

X. J. Gu

Papers

Influence of erbium on the electronic structure of Fe(65−x)Mo14C15B6Erx(x=0,1,2) bulk metallic glasses

Photoemission study of ternary to penternary Fe-based metallic glasses: Chemical analysis of surface and bulk