Metallic Glass Composite Powders Research Articles

Optimizing mechanical and electrical properties of Cu-coated Cu–Zr–Al bulk metallic glass composites by adjusting glassy powder size

In the rapidly developing modern industrial fields, the materials used are often required to have simultaneously high strength and high electrical conductivity. However, these two properties often conflict and cannot be met at the same time. In the present study, we developed the Cu/Cu–Zr–Al bulk metallic glass (BMG) composites which exhibited simultaneously high strength and high electrical conductivity, as well as large plasticity. The BMG composites were fabricated by using spark plasma sintering crystalline Cu-coated Cu–Zr–Al metallic glass composite powders. The effect of particle size of the Cu–Zr–Al metallic glass powders on mechanical properties and electrical properties of the BMG composites was investigated systematically. Microstructure of contact interfaces between crystalline Cu and Cu–Zr–Al metallic glass was also characterized and discussed. This study is expected to provide an effective technical approach for the development of new high strength and high conductivity materials.

Bulk metallic glass composites with high strength and electrical conductivity by sintering Cu-coated CuZrAl glassy powder

Abstract High strength and high electrical conductivity materials are the key materials for the development of modern electronic information and energy industries. In the present study, ultrahigh-strength Cu50Zr43Al7 metallic glass alloy is used as starting material. The crystalline Cu-coated Cu–Zr–Al metallic glass composite powders were prepared by the electroless copper plating of the metallic glass powders, then the composite powders were sintered by using spark plasma sintering (SPS) process. The fabricated Cu/Cu–Zr–Al bulk metallic glass composites exhibited simultaneously high strength and high electrical conductivity, as well as large plastic strain. The study opens a new way for development of new high strength and high conductivity materials.

Consolidation of Mechanically Alloyed Cu-Zr-Ti Metallic Glass Powders

In the present study, Cu60Zr30Ti10 metallic glass powders were prepared by mechanical alloying of pure Cu, Zr, and Ti powder mixtures. Cu60Zr30Ti10 metallic glass composite powders were obtained after 5 h of milling as confirmed by X-ray diffraction and transmission electron microscopy. The metallic glass powders were found to exhibit a supercooled liquid region before crystallization. Cu60Zr30Ti10 bulk metallic glass were synthesized by vacuum hot pressing the as-milled Cu60Zr30Ti10 metallic glass powders at 723 K in the pressure range of 0.72 ~ 1.20 GPa. Cu60Zr30Ti10 BMG with nanocrystalline precipitates homogeneously embedded in a highly dense glassy matrix was successfully prepared under applied pressures. It was found that the pressure could enhance the thermal stability and prolong the existence of amorphous phase inside Cu60Zr30Ti10 powders.

The wear properties of Ti-based bulk metallic glass composites containing carbon particles

Abstract This paper reports the preparation and wear behavior of mechanically alloyed Ti-based bulk metallic glass composites containing carbon particles. The carbon/Ti 50 Cu 28 Ni 15 Sn 7 metallic glass composite powders are formed by two-stage mechanical alloying (MA) process. The bulk metallic glass composite was successfully prepared by vacuum hot pressing of as-milled carbon/Ti 50 Cu 28 Ni 15 Sn 7 metallic glass composite powders. The differential scanning calorimeter (DSC) results show that the thermal stability of the amorphous matrix is affected by the presence of the carbon particles. Changes in T g and T x suggest deviations in the chemical composition of the amorphous matrix that were developed due to a partial dissolution of the carbon species into the amorphous phase. Although the hardness of carbon/Ti 50 Cu 28 Ni 15 Sn 7 bulk metallic glass composite is increased with carbon addition, but their wear resistances is not directly proportional to hardness and does not follow the standard wear law. The increase in the wear rate of a carbon/Ti 50 Cu 28 Ni 15 Sn 7 bulk metallic glass composite with high carbon content may be attributed to the residual porosity and in-situ formed hard TiC particles formed in situ in the matrix of the composite.

Fabrication and corrosion behavior of Ti-based bulk metallic glass composites containing carbon nanotubes

This study explored the feasibility of preparing Ti 50Cu 28Ni 15Sn 7 bulk metallic glass composite with powder metallurgy. With high energy ball milling of a pure Ti, Cu, Ni, Sn and carbon nanotube (CNT) powder mixture, the CNT/Ti 50Cu 28Ni 15Sn 7 metallic glass composite powders can be formed with mechanical alloying (MA) after 8 h milling. The bulk metallic glass composite was successfully prepared by vacuum hot pressing the as-milled CNT/Ti 50Cu 28Ni 15Sn 7 metallic glass composite powders. The corrosion behavior of the Ti 50Cu 28Ni 15Sn 7 bulk metallic glass as well as composites modified by the addition of CNT was investigated by electrochemical measurements. Electrochemical characterization was performed in Hanks’ solution at 37 °C with physiologically relevant dissolved oxygen content. The results of potentiodynamic polarization measurements revealed that the Ti-based bulk metallic glass composites examined showed spontaneous passivity by anodic polarization with a passive current density of about 10 −5 A/cm 2. The higher corrosion resistance of the Ti-based bulk metallic glass composites was attributed to stable and protective passive films enriched with titanium containing certain amounts of additional elements.

Microstructure and mechanical properties of mechanically alloyed Al 2O 3/Ti–Cu–Ni–Sn bulk metallic glass composites prepared by vacuum hot-pressing

In the present study, Ti 50Cu 28Ni 15Sn 7 metallic glass and its composite powders reinforced with 4–12 vol.% of Al 2O 3 added were successfully prepared by mechanical alloying. In the ball-milled composites, an amorphous matrix with a homogeneous dispersion of Al 2O 3 particles was developed. The metallic glass composite powders were found to exhibit a large supercooled liquid region before crystallization. The presence of Al 2O 3 particles did not change the glass formation ability of the amorphous Ti 50Cu 28Ni 15Sn 7 powders. Consolidation of the as-milled Ti 50Cu 28Ni 15Sn 7 composite powders was performed at a temperature slightly higher than the glass transition temperature under a pressure of ∼1.2 GPa; using this method, the bulk metallic glass composite discs were prepared successfully. However, partial crystallization of the amorphous matrix during the hot-pressing process was noticed. The fracture strength of consolidated composite compacts was increased with Al 2O 3 additions. The pre-existing particle boundaries may serve as the crack initiation sites which resulted in the brittle failure of the Ti 50Cu 28Ni 15Sn 7 BMG composites.

Microstructure and mechanical properties of vacuum hot-pressing SiC/Ti–Cu–Ni–Sn bulk metallic glass composites

In the present study, Ti 50Cu 28Ni 15Sn 7 (at.%) metallic glass and its composite powders reinforced with 4–12 vol.% of added SiC were successfully prepared by mechanical alloying. In the ball-milled composites, an amorphous matrix with a homogeneous dispersion of SiC particles was developed. The metallic glass composite powders were found to exhibit a large supercooled liquid region before crystallization. The presence of SiC particles did not change the glass-formation ability of the amorphous Ti 50Cu 28Ni 15Sn 7 powders. Consolidation of the as-milled Ti 50Cu 28Ni 15Sn 7 composite powders was performed at a temperature slightly higher than the glass-transition temperature under a pressure of ∼1.2 GPa; using this method, the bulk metallic glass composite discs were prepared successfully. However, partial crystallization of the amorphous matrix during the hot-pressing process was noticed. The fracture strength of consolidated composite compacts was increased with SiC additions. The pre-existing particle boundaries may serve as the crack initiation sites which resulted in the brittle failure of the Ti 50Cu 28Ni 15Sn 7 BMG composites.

기계적 밀링 및 방전 플라즈마 소결 공정을 이용한 벌크 비정질 복합재의 제조

Bulk metallic glass (BMG) composite was fabricated by consolidation of milled metallic glass composite powders. The metallic glass composite powder was synthesized by a controlled milling process using the Cu-based metallic glass powder blended with 30 vol% Zr-based metallic glass powders. The milled composite powders showed a layered structure with three metallic phases, which is formed as a result of mechanical milling. By spark plasma sintering of milled metallic glass powders in the supercooled liquid region, a fully dense BMG composite was successfully synthesized.

Effect of Carbon-Nanotube Addition on Thermal Stability of Ti-Based Metallic Glass Composites

The preparation of Ti50Cu28Ni15Sn7 metallic glass composite powders was accomplished by the mechanical alloying of a pure Ti, Cu, Ni, Sn and carbon nanotube (CNT) powder mixture after 8 h milling. In the ball-milled composites, the initial CNT particles were dissolved in the Ti-based alloy glassy matrix. The thermal stability of the amorphous matrix is affected by the presence of the CNT particles. Changes in Tg and Tx suggest deviations in the chemical composition of the glassy matrix due to a partial dissolution of the CNT species in the amorphous phase. The bulk metallic glass composite was successfully prepared by vacuum hot pressing the as-milled CNT/ Ti50Cu28Ni15Sn7 metallic glass composite powders. A significant hardness increase with the CNT additions was observed for the consolidated composite compacts.

Mechanically alloyed tungsten carbide particle/Ti 50Cu 28Ni 15Sn 7 glassy alloy matrix composites

The preparation of Ti 50Cu 28Ni 15Sn 7 (numbers indicate at.%) metallic glass composite powders was accomplished by the mechanical alloying of a pure Ti, Cu, Ni, Sn and WC powder mixture after 5 h milling. In the ball-milled composites, the initial WC particles were homogeneously dispersed in the Ti-based alloy glassy matrix. The metallic glass composite powders were found to exhibit a large supercooled liquid region before crystallization. The bulk metallic glass composite with submicron WC particles homogeneously embedded in a highly dense nanocrystalline/amorphous matrix was successfully prepared by vacuum hot pressing the as-milled WC/ Ti 50Cu 28Ni 15Sn 7 metallic glass composite powders at 723 K under a pressure of ∼1.2 GPa. A significant hardness increase with the WC additions was observed for the consolidated composite compacts.

Mg-Y-Cu Bulk Nanocrystalline Matrix Composites Containing WC Particles

The preparation of Mg49Y15Cu36 metallic glass composite powders was accomplished by mechanical alloying of pure Mg, Y, Cu, and WC powder mixture after 10 h milling. In the ball-milled composites, initial WC particles were homogeneously dispersed in the Mg-based alloy glassy matrix. The metallic glass composites powders were found to exhibit a large supercooled liquid region before crystallization. Bulk metallic glass composites were formed by vacuum hot pressing the as-milled WC/ Mg49Y15Cu36 metallic glass composite powders at 473 K in the pressure range of 0.72-1.20 GPa. BMG composite with submicron WC particles homogeneously embedded in a highly dense nanocrystalline/amorphous matrix was successfully prepared under pressure of 1.20 GPa. It was found that the applied pressure during consolidation could enhance the thermal stability and promotes nanocrystallization of WC/ Mg49Y15Cu36 BMG composites.

Thermal stability and crystallization kinetics of Cu-reinforced Cu 47Ti 33Zr 11Ni 8Si 1 metallic glass composite powders synthesized by ball milling: the effect of particulate reinforcement

The thermal stability and crystallization kinetics of Cu 47Ti 33Zr 11Ni 8Si 1 gas atomized powder (GAP) and composite powder reinforced with 25 vol.% nanosized Cu second phase particles introduced by ball milling was studied by differential scanning calorimetry in the mode of continuous heating and isothermal annealing. Ball milling leads to successful incorporation of Cu particles within the GAP matrix and hence offers itself as a useful technique to prepare composite microstructures. In the case of continuous heating, both the glass transition temperature T g and the crystallization temperature T x display a strong dependence on the heating rate. The activation energy, as determined by the Kissinger equation, for the first order transformation was found to be almost identical for the GAP (3.53±0.12 eV) and composite powders (3.59±0.06 eV). The isothermal transformation kinetics were modeled by the Johnson–Mehl–Avrami (JMA) equation. The values of the JMA exponent imply that the crystallization of the metallic glass GAP as well as the composite powder is governed by diffusion-controlled three-dimensional growth. The activation energy of crystallization derived from isothermal annealing experiments is nearly the same for the GAP (3.69±0.20 eV) and the composite powders (3.78±0.10 eV). The addition of Cu particles does not noticeably affect the crystallization kinetics of the amorphous matrix composites.

Cu-Zr-Ti Bulk Metallic Glass Composites Produced by Mechanical Alloying and Vacuum Hot-Pressing

In the present study, WC/Cu60Zr30Ti10 metallic glass composite powders were prepared by mechanical alloying of pure Cu, Zr, Ti, and WC powder mixtures. Cu60Zr30Ti10 metallic glass composite powders were obtained after 5 h of milling as confirmed by X-ray diffraction and differential scanning calorimetry. The metallic glass composites powders were found to exhibit a supercooled liquid region before crystallization. Bulk metallic glass (BMG) composites were synthesized by vacuum hot pressing the as-milled Cu60Zr30Ti10 metallic glass composite powders at 723 K in the pressure range of 0.72-1.20 GPa. BMG composite with submicron WC particles homogeneously embedded in a highly dense anocrystalline/amorphous matrix was successfully prepared under applied pressure of 1.20 GPa. It was found that the pressure could enhance the thermal stability and promotes nocrystallization of WC/Cu60Zr30Ti10 BMG composites.

Synthesis of Ti-Based Bulk Metallic Glass Composites Containing WC Particles

The preparation of Ti50Cu28Ni15Sn7 metallic glass composite powders was accomplished by mechanical alloying of pure Ti, Cu, Ni, Sn and WC for 18 ks. In the ball-milled composites, initial WC particles were homogeneously dispersed in the Ti-based alloy glassy matrix. The metallic glass composite powders exhibited a large supercooled liquid region just below the crystallization temperature. The presence of WC nanoparticles did not change the glass formation ability of amorphous Ti50Cu28Ni15Sn7 powders. The as-milled Ti50Cu28Ni15Sn7 and composite powders were consolidated by vacuum hot pressing into compact discs with a diameter and thickness of 10 and 4 mm, respectively. Microstructural analysis showed that the bulk metallic glass composite contained submicron WC particles homogeneously embedded in a highly dense nanocrystalline/amorphous matrix. Incorporation of WC into consolidated composite compacts resulted in a significant increase in hardness.