Metallic Glassy Alloy Powders Research Articles

Mechanical properties and corrosion resistance of large-size biodegradable Ca–Mg–Zn bulk metallic glasses fabricated via powder metallurgy

Biodegradable metallic glasses are used as disposable green devices whose constituents decompose into harmless byproducts, leaving no residual waste and requiring no removal surgery. Here, the large size Ca-based (Ca65Mg15Zn20) bulk metallic glasses (BMGs) were fabricated by consolidating gas-atomized metallic glassy alloy powder using a spark plasma sintering (SPS) technique. The effects of sintering temperature on structure, mechanical properties, and biodegradation rate of the developed Ca-based BMGs in Hank's solution were evaluated. The high-strength consolidated samples with a fully glassy phase and suitable biodegradation rate were produced by the SPS process at a sintering temperature of 120 °C with a loading pressure of 600 MPa. The Ca–Mg–Zn bulk metallic glass alloys developed by the SPS process can offer excellent properties and satisfy large sample-size requirements, which opens possibilities of application as biodegradable materials.

Potential applications of cold sprayed Cu50Ti20Ni30 metallic glassy alloy powders for antibacterial protective coating in medical and food sectors

Mechanical alloying was utilized for synthesizing of metallic glassy Cu50Ti20Ni30 alloy powders, using a low energy ball milling technique. The metallic glassy powders obtained after 100 h of ball milling had an average particle size of 1.7 mm in diameter and possessed excellent thermal stability, indexed by a relatively high glass transition temperature (358.3 oC) with a wide supercooled liquid region (61 oC). This amorphous phase crystallized into Ti2Cu and CuTiNi2 ordered phases through two overlapped crystallization temperatures at 419.3 oC and 447.5 oC, respectively. The total enthalpy change of crystallization was −4.8 kJ/mol. The glassy powders were employed as feedstock materials to double-face coating the surface of SUS 304 substrate, using cold spraying process under helium gas pressure at 400 oC. This coating material had an extraordinary high nanohardness value of 3.1 GPa. Moreover, it showed a high resistance to wear with a low value of the coefficient of friction ranging from 0.45 to 0.45. Biofilms were grown on 20-mm2 SUS304 sheets coated coupons inoculated with 1.5 × 108 CFU ml−1E. coli. Significant biofilm inhibition (p The inhibition of biofilm formation by nanocrystalline powders of Cu-based provides a practical approach to achieve the inhibition of biofilms formation.

Consolidation Behavior of Cu-Zr-Al Metallic Glass Powder by Spark Plasma Sintering

We investigated consolidation behavior of gas-atomized Cu50Zr45Al5 metallic glassy alloy powders by a spark plasma sintering (SPS) process. Density of the sintered samples increased with an increase in sintering temperature. The nearly full density samples without crystallization could be attained by the SPS process at sintering temperature of 693 K under pressure of 600 MPa. The produced samples exhibited high-strength and met large-size requirement. The SPS process makes it possible to fabricate the large-size bulk metallic glasses without limitation of dimensions and alloy system.

Microwave-Induced Sintering of Cu-Based Metallic Glass Matrix Composites in a Single-Mode 915-MHz Applicator

Using a single-mode 915-MHz microwave applicator equipped with a ceramic pressing unit, we processed the gas-atomized Cu50Zr45Al5 metallic glassy alloy powder blended with Sn powder of various contents in a separated magnetic (H-) field maximum. The blended powders were well heated in H-field. Bulk Cu50Zr45Al5 metallic glass matrix composites were produced with an applied pressure of 5 MPa. As a secondary phase, the Sn particle promoted the densification of the sintered samples.

Microstructure and mechanical properties of crystalline particulates dispersed Ni-based metallic glassy composites fabricated by spark plasma sintering

Using the mixed powders of the gas-atomized Ni-based metallic glassy alloy powder blended with metal W or ceramic SiC particulates, we fabricated large-size bulk glassy alloy composites (GACs) by a spark plasma sintering (SPS) process. The microstructure and mechanical properties of the prepared GAC specimens were investigated, and the effect of addition amount of the crystalline particulates on the properties of the sintered GAC specimens was discussed. The Ni-based bulk GACs with ultrahigh strength and enhanced plasticity were produced. The improvement of plasticity of the fabricated bulk GACs is attributed to the structural inhomogeneity caused by the addition particulates inclusion. The optimum content of the crystalline particulates is about 5–10 vol.%.

Ni-Nb-Sn Bulk Metallic Glass Matrix Composites Fabricated by Microwave-Induced Sintering Process

Using a gas-atomized Ni59.35Nb34.45Sn6.2 metallic glassy alloy powder blended with Sn powder of various contents, Ni-Nb-Sn bulk metallic glassy matrix composites were fabricated by a microwave (MW)–induced sintering process in a single-mode 2.45 GHz MW applicator in a separated magnetic field. The Ni59.35Nb34.45Sn6.2 glassy alloy powder and its mixed powders containing Sn particles could be heated well in the magnetic field. The addition of Sn particles promoted densification of the sintered Ni59.35Nb34.45Sn6.2 metallic glassy powder. Bulk samples without crystallization of the glassy matrix and with good bonding state among the particles were achieved at a sintering temperature of 833 K.

Dual phase metallic glassy composites with large-size and ultra-high strength fabricated by spark plasma sintering

Two-phase bulk metallic glasses (BMGs) have attracted increasing interest since phase separation might produce metallic glasses with new physical and mechanical properties. In this study, we fabricated the dual phase glassy BMG composites by a spark plasma sintering process using a mixed powder of the gas-atomized Ni-based and Fe-based metallic glassy alloy powders. The thermal stability, microstructure, mechanical and magnetic properties of the obtained dual-phase glassy composites were investigated. The dual-phase glassy composites exhibited ultra-high strength and good soft magnetic properties which satisfy large-size requirements.

Densification of Gas Atomized Ni-Based Metallic Glassy Powders by Spark Plasma Sintering

Gas-atomized Ni52:5Nb10Zr15Ti15Pt7:5 metallic glassy alloy powders were consolidated by a spark plasma sintering (SPS) process. The densification behavior during the SPS process as well as the structure, thermal stability and mechanical properties of the sintered specimens were investigated. The glassy alloy powders were densified rapidly when the temperature exceeded about 740 K. The density of the sintered specimens increased with an increase in sintering temperature. The specimens with full densification and no crystallization were obtained by the SPS process at a sintering temperature of 773 K with a loading pressure of 600 MPa. The sintered specimens exhibit high-strength and can meet large-size requirement. [doi:10.2320/matertrans.ME200817]

Microwave-induced sintering of NiNbTiPt metallic glass blended with Sn powders using a single-mode applicator

Microwave (MW) processing is emerging as an innovative and highly effective material processing method offering many advantages over conventional methods especially for sintering application. In the present study, using a mixed powder of the Ni55Nb25Ti15Pt5metallic glassy powder prepared by an argon gas atomization process blended with 50 vol.% Sn powder, the MW-induced heating and sintering were carried out by a single-mode 2.45 GHz MW applicator in a magnetic field maximum. The structure and thermal stability of the sintered glassy composite specimens were investigated. The addition of Sn particles enhanced densification of the sintered Ni-based metallic glassy alloy powders.

Effect of Sn on microwave-induced heating and sintering of Ni-based metallic glassy alloy powders

Microwave (MW)-induced heating and sintering was carried out by a single-mode MW applicator in a separated electric field or magnetic field using the gas-atomized Ni 52.5Nb 10Zr 15Ti 15Pt 7.5 metallic glassy alloy powder blended with various contents of Sn powders. The addition of Sn particles was found to promote the densification of the sintered Ni-based metallic glassy powders. With increasing Sn contents, the sintering temperature to obtain bulk sample with the retention of the glassy structure was reduced, and good bonding between powder particles was achieved.

Fabrication of Ni-Nb-Sn Metallic Glassy Alloy Powder and its Microwave-Induced Sintering Behavior

In the present study, we prepared Ni59.35Nb34.45Sn6.2 metallic glassy alloy powder by an argon gas atomization process. Microwave (MW)-induced heating and sintering was carried out by a singlemode 2.45 GHz MW applicator in the separated magnetic field or electric field using the obtained glassy powders. The structure and thermal stability of the sintered glassy alloy specimens were investigated.

Fabrication of ZrCuAlNi Metallic Glassy Matrix Composite Containing ZrO<SUB>2</SUB> Particles by Spark Plasma Sintering Process

Using a mixed powder of argon gas-atomized Zr 55 Cu 30 Alj o N1 5 metallic glassy alloy powder blended with 10vol% ZrO 2 powder, Zr 55 Cu 30 Al 10 Ni 5 bulk metallic glassy matrix composite was fabricated by a spark plasma sintering process. The structure, thermal stability and mechanical properties of the sintered bulk metallic glassy matrix composite were investigated. The ZrO 2 particles were homogeneously dispersed in the Zr 55 Cu 30 Al 10 Ni 5 glassy matrix. No crystallization of the glassy matrix occurred during the spark plasma sintering process. The crystallization behavior of the sintered composite was similar to that of the metallic glassy powder. The sintered composite specimen exhibited larger plastic ductility than that of the as-cast Zr 55 Cu 30 Al 10 Ni 5 glassy alloy rod specimen. The increase in the plastic ductility is proposed to originate from the structural inhomogeneity caused by the ZrO 2 ceramic particles.

Reviewers volume 8

Biodegradable metallic glasses are used as disposable green devices whose constituents decompose into harmless byproducts, leaving no residual waste and requiring no removal surgery. Here, the large size Ca-based (Ca65Mg15Zn20) bulk metallic glasses (BMGs) were fabricated by consolidating gas-atomized metallic glassy alloy powder using a spark plasma sintering (SPS) technique. The effects of sintering temperature on structure, mechanical properties, and biodegradation rate of the developed Ca-based BMGs in Hank's solution were evaluated. The high-strength consolidated samples with a fully glassy phase and suitable biodegradation rate were produced by the SPS process at a sintering temperature of 120 °C with a loading pressure of 600 MPa. The Ca–Mg–Zn bulk metallic glass alloys developed by the SPS process can offer excellent properties and satisfy large sample-size requirements, which opens possibilities of application as biodegradable materials.