scholarly journals Structure and Properties of Zr-Based Bulk Metallic Glasses in As-Cast State and After Laser Welding

Materials ◽  
2018 ◽  
Vol 11 (7) ◽  
pp. 1117 ◽  
Author(s):  
Wirginia Pilarczyk
Keyword(s):  
Laser Welding ◽  
Metallic Glasses ◽  
Bulk Metallic Glasses ◽  
Structure And Properties ◽  
Cast State

scholarly journals A Conflict of Fineness and Stability: Platinum- and Palladium-Based Bulk Metallic Glasses for Jewellery

2020 ◽  
Author(s):  
O. S. Houghton ◽  
A. L. Greer
Keyword(s):  
Metallic Glasses ◽  
Bulk Metallic Glasses ◽  
Precious Metals ◽  
High Hardness ◽  
Scratch Resistance ◽  
Cast State ◽  
High Definition ◽  
Glass Forming ◽  
Thermoplastic Forming ◽  
Near Net Shape

For the metals used in jewellery, high hardness and the associated scratch resistance are much sought after. Conventional crystalline alloys for jewellery are alloyed and extensively processed (thermally and mechanically) to improve hardness, but it is difficult to reach values beyond 300 HV. The advent of bulk metallic glasses, based on precious metals and with hardness exceeding 300 HV in the as-cast state, is therefore of great interest for both jewellery and watchmaking. The non-crystalline structure of these materials not only gives high hardness, but also the opportunity to shape metals like plastics, via thermoplastic forming. For more traditional jewellery manufacture, bulk metallic glasses also exhibit high-definition and near-net-shape casting. Gold-based alloys have long dominated the consideration of bulk metallic glasses for jewellery as they can comply with 18K hallmarks. Although bulk metallic glasses based on platinum or palladium possess excellent thermoplastic formability, and are without known tarnishing problems, achieving useful glass-forming ability within the more restrictive hallmarking standards typically used for jewellery (≥95 wt.% Pt or Pd) is, at best, challenging. In this review, platinum- and palladium-based bulk metallic glasses are discussed, focusing on their potential application in jewellery and on the further research that is necessary.

Structural, Magnetic and Crystallization Study of Fe-Based Bulk Metallic Glasses

2013 ◽  
Vol 203-204 ◽  
pp. 288-291 ◽  
Author(s):  
Rafał Babilas ◽  
Ryszard Nowosielski ◽  
Wirginia Pilarczyk ◽  
Grzegorz Dercz
Keyword(s):  
Magnetic Properties ◽  
Magnetic Permeability ◽  
Metallic Glasses ◽  
Bulk Metallic Glasses ◽  
Annealing Process ◽  
Bulk Amorphous Alloy ◽  
X Ray Diffraction ◽  
Cast State ◽  
Scanning Calorimetry ◽  
Crystallization Study

The work presents the structural, thermal and magnetic properties analysis of Fe72B20Si4Nb4 bulk metallic glasses in as-cast state and crystallization study of bulk amorphous alloy after annealing process. The studies were performed on bulk metallic glasses in of rods form with diameter of 1,5 and 2 mm. The structure analysis of the samples in as-cast state and phase analysis of studied alloy after annealing process was carried out by the X-ray diffraction (XRD) methods. Mössbauer spectroscopy (MS) was also used to investigate the local structure for studied bulk metallic glasses. Thermal properties associated with glass transition, onset and peak crystallization temperatures was examined by differential scanning calorimetry (DSC). The soft magnetic properties examination of tested material contained initial magnetic permeability and disaccommodation of magnetic permeability.

scholarly journals Structure and Properties of Mg-Cu-(Y,Ca) Bulk Metallic Glasses / Struktura I Własności Masywnych Szkieł Metalicznych Mg-Cu-(Y,Ca)

2015 ◽  
Vol 60 (4) ◽  
pp. 2645-2650 ◽  
Author(s):  
R. Babilas ◽  
K. Cesarz-Andraczke ◽  
R. Nowosielski
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Metallic Glasses ◽  
Crystallization Process ◽  
Bulk Metallic Glasses ◽  
Structure Characterization ◽  
Cast State ◽  
Preparation Methods ◽  
X Ray ◽  
Stage Crystallization

The work presents preparation methods, structure characterization and mechanical properties analysis of Mg-based bulk metallic glasses in as-cast state and after crystallization process. The studies were performed on Mg60Cu30Y10 and Mg37Cu36Ca27 glassy alloys in the form of plates and rods. The X-ray diffraction investigations revealed that the tested samples with different thicknesses and shapes were amorphous. The characteristics of the fractured surfaces showed mixed fractures with the “river” and “mirror” patterns, which are characteristic for the glassy materials and some “smooth” areas. The samples of Mg37Cu36Ca27 alloy presented a two-stage crystallization process, but addition of Y caused a single stage crystallization behavior. Qualitative phase analysis from the X-ray data of examined alloys annealed at 473 K enabled the identification of Mg, Mg2Cu, Cu2Mg and CaCu crystalline phases. The changes of compressive strength as a function of annealing temperature for studied rods were stated. The best mechanical properties including microhardness and compressive strength were obtained for the alloy with the addition of Y in as-cast state.

Formation, structure and properties of pseudo-high entropy clustered bulk metallic glasses

2020 ◽  
Vol 820 ◽  
pp. 153164
Author(s):  
A. Inoue ◽  
F.L. Kong ◽  
S.L. Zhu ◽  
B.L. Shen ◽  
A. Churyumov ◽  
...  
Keyword(s):  
Metallic Glasses ◽  
Bulk Metallic Glasses ◽  
Structure And Properties ◽  
High Entropy

Structure and Corrosion Behavior of Mg-Cu-Y-(Zn,Ni) Bulk Metallic Glasses

2015 ◽  
Vol 227 ◽  
pp. 23-26
Author(s):  
Rafał Babilas ◽  
Katarzyna Cesarz-Andraczke ◽  
Dorota Babilas ◽  
Wojciech Simka
Keyword(s):  
Corrosion Behavior ◽  
Metallic Glasses ◽  
Amorphous Alloys ◽  
Bulk Metallic Glasses ◽  
Pure Magnesium ◽  
Cast State ◽  
Surface Layers ◽  
Glassy Alloys ◽  
Ni Addition ◽  
Better Than

The work presents a structural and corrosion resistance analysis of Mg-based bulk metallic glasses in “as-cast” state. The studies were performed on bulk glassy samples in the form of plates. The structure analysis of the samples in “as-cast” state was carried out by the XRD and DSC methods. The corrosion behavior of the bulk glassy alloys and pure magnesium samples was studied by electrochemical measurements and immersion tests in 5% NaCl solution at room temperature. For the amorphous alloys the highest corrosion potential was achieved, indicating the formation of protective surface layers with Mg and Cu oxides. The corrosion behavior of the alloys with Zn and Ni addition was found to be better than pure magnesium.

A Gold-Based Bulk-Solidifying Amorphous Alloy for Jewelry — Comparison with a Palladium-Based Amorphous Alloy

2014 ◽  
Vol 783-786 ◽  
pp. 1901-1906 ◽  
Author(s):  
Sandrine Cardinal ◽  
Ji Chao Qiao ◽  
Jean Marc Pelletier
Keyword(s):  
Amorphous Alloy ◽  
Shear Modulus ◽  
Metallic Glasses ◽  
Cold Working ◽  
Bulk Metallic Glasses ◽  
High Hardness ◽  
Gold Alloys ◽  
Cast State ◽  
Casting Technique ◽  
Aesthetic Appearance

The gold alloys are used in jewelry for their aesthetic appearance and inertia to the environment. In jewelry a hardness superior to 300 HV is desirable to facilitate the final machining and reduce the wear of the final product. The maximum hardness that can be obtained with the standard 18 carats gold (Au75-Ag12.5-Cu12.5 (wt%)) through a combination of heat treatment and cold working is about 290 HV. Gold-based bulk metallic glasses (BMGs) are an alternative as they present unique properties in comparison with crystalline counterparts, especially easy thermoplastic processing combined with a high hardness. Pd-base BMGs are another solution, due also to their attractive features.An Au49Cu26.9Si16.3Ag5.5Pd2.3 (% at.) and a Pd40Cu30Ni10P20 (% at.) bulk metallic glasses were fabricated by a copper mould suction casting technique in an argon atmosphere. In the as-cast state hardness, shear modulus and hardness are high (HV0.3= 360 and 530 in the Au-and Pd-base BMGs, respectively). Various heat treatments have been performed to modify the microstructural state. Formation of crystalline particles induces an increase of both shear modulus and hardness but a drastic decrease in toughness and therefore this formation should be absolutely avoided during casting or thermo processing.

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