In this study, enhancement of glass forming ability (GFA) as well as mechanical and magnetic properties of a Fe-based bulk metallic glass (BMG) was investigated with minor addition of Cu. The obtained results revealed that appropriate addition of Cu could significantly improve GFA of the base BMG. Furthermore, the mechanical properties of the investigated BMG were improved by the addition of 25 at.% Cu due to the positive heat of mixing between Cu and Fe atoms, decreasing the free volume and density of porosities. Therefore, the relatively good and comprehensive properties of the BMG containing 0.25 at.% Cu were exhibited; also, as a result of an excellent combination of good GFA (ΔTx = 48 K), microhardness (1425 HV), failure strain (ef = 2.1%), and failure strength (σf = 4400 MPa) was created it as a promising candidate for engineering applications. Furthermore, the magnetic measurements revealed that ferromagnetic properties of this Fe-based BMG decreased with the addition of 0.25 at.% Cu, but increased significantly with the addition of 0.5 at.% Cu.

Enhanced glass forming ability, mechanical, and magnetic properties of Fe 41 Co 7 Cr 15 Mo 14 Y 2 C 15 B 6 bulk metallic glass with minor addition of Cu

In this work, we report the thickness effects on microstructure, mechanical and soft magnetic properties of Fe75Zr25 thin film metallic glasses (TFMGs) prepared by DC magnetron sputtering. The Fe75Zr25 TFMGs exhibit a nano-granular structure and the particle size is growing with the increase of thickness. The hardness (H) and the elastic modulus (E) evaluated by nanoindentation, both show a decreasing trend with the increase of film thickness. The smooth P-h curves reflect a homogenous deformation mode, which is attributed to the activation of shear transformation zones (STZs) in the nanoscale granular thin films that could reasonably restrain the formation of shear bands. Furthermore, a positive strain rate dependence was observed for all films with highest strain rate sensitivity SRS (m) value of 0.037 for thicker film, more likely due to the free volumes accumulation during deformation. In addition, Fe75Zr25 TFMGs show anomalous strong ferromagnetism at low and high temperatures (10 K and 300 K). It is found that in a critical thickness of 270 nm, the Fe75Zr25 TFMGs manifest the desired combination of soft magnetism and mechanics. The underlying mechanism of variation in mechanical and soft magnetic properties could be rationalized in light of the interplay of nanoscale granular size and structural evolution with increase of film thickness. This study offers a paradigm to design Fe-based TFMGs with simultaneously superior mechanical performance and excellent soft magnetic properties.

Thickness effects on microstructure, mechanical and soft magnetic properties of sputtered Fe Zr thin film metallic glass

Investigation of the effects of Al on the glass forming ability of Zr-Cu-Ni-Al alloys through their solidification characteristics

We developed novel Ti-Zr-Be-Co bulk metallic glasses through Co addition based on a ternary Ti45Zr20Be35 alloy. By altering the alloying routes and alloying contents, the influence of Co alloying on glass-forming ability, thermal stability, thermoplastic formability, crystallization behavior, and corrosion resistance has been investigated systematically. It was found that the best alloying route for enhancing the glass-forming ability, thermoplastic formability, compressive plasticity, and corrosion resistance is to replace Be by Co. Ti45Zr20Be23Co12 possesses the largest critical diameter of 15 mm for glass formation. Ti45Zr20Be27Co8 possesses the highest thermoplastic formability which is comparable to that of Vitreloy alloys. Ti45Zr20Be25Co10 exhibits the largest room temperature plasticity of 15.7% together with a high specific strength of 3.90 × 105 Nm/kg. The addition of Co also strongly affects the crystallization behavior of the base alloy, resulting in a more complex crystallization process. The corrosion resistance of Ti-Zr-Be alloy in 1 mol/L HCl solution can also be enhanced by Co alloying. The related mechanisms have been explained in detail, which provide guidance for the composition design of Ti-based metallic glasses with improved properties.

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Preparation, Characterization, and Properties of Novel Ti-Zr-Be-Co Bulk Metallic Glasses

In this research work, iron-based bulk metallic glasses (BMGs) have been fabricated, characterized and compared with Fe-Si alloy BMG alloys of composition ((Fe06Co04)075B020Si005)96Nb4) were synthesized by suction casting technique using chilled copper die Effect of copper and zirconium addition on magnetic, mechanical, thermal and electrochemical behavior of ((Fe06Co04)075B020Si005)96Nb4 BMGs was investigated Furthermore, effect of annealing on nano-crystallization and subsequently on magnetic and mechanical behavior was also analyzed Amorphousness of structure was evidenced by XRD analysis and microscopic visualization, whereas nano-crystallization behavior was identified by peak broadening of XRD patterns Magnetic properties, measured by vibrating sample magnetometer, were found to be improved for as-cast BMG alloys by copper addition and further enhanced by nano-crystallization after annealing Mechanical properties were observed to be increased by zirconium addition while slightly declined by copper addition Potentiodynamic polarization analysis manifested the positive role of zirconium in enhancing corrosion resistance of BMGs in acidic, basic and brine mediums Moreover, mechanical properties and corrosion analysis results affirmed the superiority of BMG alloys over Fe-Si alloy

Effect of Copper and Zirconium Addition on Properties of Fe-Co-Si-B-Nb Bulk Metallic Glasses

In this paper the role of copper addition has been studied to examine thermal, mechanical, magnetic and corrosion properties of the Fe43Co22Ni7B19Si5Nb4 bulk metallic glass alloy material. It is found that the copper addition in alloys exhibited low supercooled liquid region as compared to copper-free alloy. It is observed that microhardness was reduced in Cu-containing alloy with generation of shear bands along faces of micro indent impression while in Cu-free alloy straight and long microcracks appeared at the indent corners indicating its brittle behavior. The magnetic properties slightly decrease with Cu addition however the corrosion resistance of Cu-containing alloy showed superior properties indicating commercial benefits in aggressive environment.

Sidra Jilani

Papers

Role of copper addition on properties of bulk metallic glass materials