Estimation of the Glass Forming Ability of the Fe-based Bulk Metallic Glass Fe68.8C7.0Si3.5B5.0P9.6Cr2.1Mo2.0Al2.0 that Contains Non-metallic Inclusions

Hongxiang Li,Zhaoping Lu,이승훈 대한금속·재료학회 2009 METALS AND MATERIALS International Vol.15 No.1

For the mass production of bulk metallic glasses, the use of industrial raw materials that contain certain amounts of inclusions is inevitable. The glass-forming ability of bulk metallic glasses, i.e., the critical cooling rate for glass formation upon solidification, is closely related to the nature of heterogeneous nucleation offered by inclusions during the solidification process. Significantly different effects of various types of inclusions on the glass forming ability of the alloy Fe68.8C7.0Si3.5B5.0P9.6Cr2.1Mo2.0Al2.0 are demonstrated in this study. The origins of the effects of different inclusions on the glass forming ability are analyzed through thermodynamic, crystallographic and classical heterogeneous nucleation kinetic theories. For the mass production of bulk metallic glasses, the use of industrial raw materials that contain certain amounts of inclusions is inevitable. The glass-forming ability of bulk metallic glasses, i.e., the critical cooling rate for glass formation upon solidification, is closely related to the nature of heterogeneous nucleation offered by inclusions during the solidification process. Significantly different effects of various types of inclusions on the glass forming ability of the alloy Fe68.8C7.0Si3.5B5.0P9.6Cr2.1Mo2.0Al2.0 are demonstrated in this study. The origins of the effects of different inclusions on the glass forming ability are analyzed through thermodynamic, crystallographic and classical heterogeneous nucleation kinetic theories.

NdFeB 자석 스크랩을 이용한 Mg-Cu-Gd-Nd 비정질 합금의 제조 및 특성

윤덕환,민홍,채홍준,이진규 대한금속·재료학회 2019 대한금속·재료학회지 Vol.57 No.10

In the present study, new Mg-based bulk metallic glasses have been developed in a Mg-Cu-Gd- Nd based system using a Mg-Nd byproduct obtained from the recycling process of NdFeB magnet scrap through liquid metal extraction. The Mg-Cu-Gd-Nd bulk metallic glasses with a diameter of 2 mm are fabricated by injection casting using Mg-Nd by-product. The compressive fracture strength and total strain are 850 MPa and 1.8%, respectively, for the Mg66.5-xCu28.5GdxNd5(x=8, 10 at%) bulk metallic glasses. The activation energy of the Mg56.5Cu28.5Gd10Nd5 bulk metallic glass using Mg-Nd byproduct is similar to that of conventional Mg56.5Cu28.5Gd10Nd5 bulk metallic glass using pure elements, indicating that the thermal stability in the supercooled liquid region is similar. From the results, the recycling process for NdFeB magnet scrap can be considered a cost effective method for the formation of Mg-based bulk metallic glasses. It can therefore be concluded that the newly developed Mg-Cu-Gd-Nd bulk metallic glasses using Mg-Nd byproduct obtained from the recycling process of NdFeB magnet scrap have potential for industrial application.

방전플라즈마 소결법에 의한 비정질/비정질 복합재의 제조

이진규,Lee, Jin-Kyu 한국분말야금학회 2007 한국분말재료학회지 (KPMI) Vol.14 No.6

The Cu-based bulk metallic glass (BMG) composites containing Zr-based metallic glass phase have been consolidated by spark plasma sintering using the mixture of Cu-based and Zr-based metallic glass powders in their overlapped supercooled liquid region. The Zr-based metallic glass phases are well distributed homogeneously in the Cu-based metallic glass matrix after consolidation process. The successful consolidation of BMG composites with dual amorphous phases was corresponding to the sound viscous flow of the two kinds of metallic glass powders in their overlapped supercooled liquid region.

Zr계 Vitreloy 박막의 특성에 대한 조사

이경민,이병준,김병훈,이의완,박동수 慶北大學校 師範大學 科學敎育硏究所 1999 科學敎育硏究誌 Vol.23 No.-

We have grown Zr based vitreloy alloy thin films by thermal deposition methode and ion beam sputtering method and compared them with Zr-Ti-Cu-Ni-Be bulk metallic glass bulk. Thermal analysis caused Zr-Ti-Cu-Ni-Be bulk metallic glass to recrystallize in the two region. The onset point temperature of the first region was 414.12℃ and the peak temperature was 410.02℃. The onset point temperature of the second region was 445.21℃ and the peak point temperature was 454.45℃. The X-ray diffraction measurement and thermal analysis as a function of temperature showed that the bulk metallic glass thin films recrystallize in the same temperature region. As a result, Zr based vitreloy alloy was the same as phase transition of bulk metallic glass bulk and bulk metallic glass thin film.

Amorphous phase separation in an Fe-based bulk metallic glass

Guo, Wei,Choi, Pyuck-Pa,Seol, Jae-Bok Elsevier 2017 Materials letters Vol.190 No.-

<P><B>Abstract</B></P> <P>Although lanthanide elements play a critical role in increasing the glass forming ability and mechanical property alternation of Fe based bulk metallic glass (Fe-BMG), the atomic scale configuration of lanthanide in Fe-BMG remained unexplored. Here we have studied atomic configuration in the amorphous state of as-cast 4mm FeCoCrMoCBY bulk metallic glass sheet and its mechanical properties by nanoindentation, transmission electron microscopy, and atom probe tomography. The current results showed that yttrium rich clusters are enriched with carbon atoms in the amorphous state, and the three dimensional densities of these clusters can influence the hardness at the localized region. The finding of Y-C rich clusters also suggests that the amorphous phase separation can precede the devitrification process.</P> <P><B>Highlights</B></P> <P> <UL> <LI> 4mm thick FeCoCrMoCBY bulk metallic glass sheet was successfully synthesized. </LI> <LI> Atomic scale characterization of amorphous phase separation preceding crystallization. </LI> <LI> Yttrium-carbon enriched nanoclusters was observed in amorphous state. </LI> <LI> The nanohardness increased with increasing spatial density of yttrium-carbon clusters. </LI> <LI> Propose new clues how yttrium increased the glass forming ability of Fe-bulk metallic glass. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

방전 플라즈마 소결법을 이용한 Al-Ni-Co-Y 벌크 비정질 합금의 제조

이정표,이진규 한국분말재료학회 2023 한국분말재료학회지 (KPMI) Vol.30 No.1

In this study, an Al82Ni7Co3Y8 (at%) bulk metallic glass is fabricated using gas-atomized Al82Ni7Co3Y8 metallic glass powder and subsequent spark plasma sintering (SPS). The effect of powder size on the consolidation of bulk metallic glass is considered by dividing it into 5 m or less and 20–45 m. The sintered Al82Ni7Co3Y8 bulk metallic glasses exhibit crystallization behavior and crystallization enthalpy similar to those of the Al82Ni7Co3Y8 powder with 5 m or less and it is confirmed that no crystallization occurred during the sintering process. From these results, we conclude that the Z-position-controlled spark plasma sintering process, using superplastic deformation by viscous flow in the supercooled liquid-phase region of amorphous powder, is an effective process for manufacturing bulk metallic glass.

Development of Cu-Hf-Al Ternary Systems and Tungsten Wire/Particle Reinforced Cu48Hf43Al9 Bulk Metallic Glass Composites for Strengthening

임혜인,안지헤,박조영 한국물리학회 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.56 No.2

Stable bulk glass forming alloys can be developed over a wide range of compositions in Cu-Hf-Al ternary systems starting from the Cu49Hf42Al9 bulk metallic glass. Ternary Cu-Hf-Al alloys can be cast directly from the melt into copper molds to form fully amorphous strips with thicknesses of 1 to 6 mm. The maximum critical diameter of the new Cu-Hf-Al ternary alloy was 6 mm. X-ray diffraction patterns were used to confirm the amorphous nature of the ternary Cu-Hf-Al alloys. To increase the toughness of these metallic glasses, we reinforced the Cu48Hf43Al9 bulk metallic glass-forming liquid with a 50% volume fraction of tungsten particles and an 80% volume fraction of tungsten wires with diameters of 242.4 µm. Composites with a critical diameter of 7mm and length 70 mm were synthesized. The structure of the composites was confirmed by using X-ray diffraction (XRD), and the scanning electron microscopy (SEM). The mechanical properties of the composites were studied in compression tests. The thermal stability and the crystallization processes of the Cu-Hf-Al alloys and composites were investigated by using differential scanning calorimetry (DSC). Values of the glass transition temperature (Tg), the crystallization temperature (Tx), and the supercooled liquid region (ΔT = Tx - Tg) are given in this paper.

벌크 비정질 금속의 마찰접합에 미치는 접합계면 온도의 영향

박정수(Jung-Soo Park),정윤철(Yoon-Chul Jung),신형섭(Hyung-Seop Shin) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.5

This study aims to investigate the how the temperature distribution at the joining interface influence on the weld characteristic of dissimilar friction welding of bulk metallic glasses(BMG) to crystalline metals. An infrared thermal imager (FLIR-ThermaCam SC-2000) was used to measure the temperature distribution at joining interface of the specimens during friction welding. Understanding the temperature distribution on the joining interface is important, because not only it determines whether the friction welding will be implemented successfully or not, but also it influences the residual stress, the crystallization of amorphous phase, and the eventually strength of the welds. A successful welding is achieved by using a friction welding apparatus which incorporates a pneumatic actuator and gripper to give a precise control of the friction time and pressure. The shape of the protrusion formed at the weld interface were examined. A Zr??Cu₄?Al₁? bulk metallic glasses and crystalline metals of Ti-alloys and Al-alloys were adopted as samples. In order to characterize the friction welded interface, the micrographic observation and the X-ray diffraction analysis on the weld cross-section were carried out. The obtained results were disussed based on the temperature distribution measured at the weld interface A successful joining of the bulk metallic glasses(BMG) to crystalline metals could be obtained for certain pairs of the material combination through the precise control of friction conditions. The residual strength after welding was evaluated by the four-point bending test and compared with the cases of friction welding to similar materials.

Effect of Sn on Plastic Deformation Ability of Fe–Si–B–P–Sn bulk Metallic Glasses

Xiaoyu Wu,Xining Li,Xue Li,Shengli Li 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.12

Fe-based bulk metallic glasses have the advantages of high strength and low coercivity. However, their plastic deformationability is negligible. Therefore, in this study, Sn was added to a Fe–Si–B–P bulk metallic glass matrix to study its influence onthe formation and plastic deformation ability of Fe–Si–B–P bulk metallic glasses. The results showed that the mixing enthalpyof Sn was less than that of Fe and other metal-like atoms, which caused Sn atoms to separate from Si-, B- and P-centeredclusters, resulting in metal-like clusters not occupying adjacent positions and the voids between clusters being occupied bySn atoms. With increasing Sn, the metal-metal bonds of the linked clusters increased and the macroscopic performance wasmanifested in an improvement in the plastic deformation ability. With 0.3 at% Sn addition, the alloy system showed the bestplastic deformation ability increasing from 0.7 to 2.2% and the yield strength of 3150 MPa.

Fabrication of bulk metallic glasses in the alloy system Fe–C–Si–B–P–Cr–Mo–Al using hot metal and industrial ferro-alloys

Li, Hongxiang,Yi, Seonghoon Elsevier 2007 Materials science & engineering. properties, micro Vol.449 No.-

<P><B>Abstract</B></P><P>Fe-base bulk metallic glasses in the alloy system Fe–C–Si–B–P–Cr–Mo–Al have been developed using hot metal and industrial ferro-alloys. The amorphous alloys can be cast into fully amorphous rods with diameters of up to 4mm, demonstrating high glass-forming ability and high strength (>3GPa). Thermal stability and crystallization behavior of the Fe–C–Si–B–P–Cr–Mo–Al bulk metallic glasses are also investigated. The Fe-base bulk metallic glasses can be produced cost-effectively and massively for extensive structural applications.</P>