Ivan Lobzenko^1,*, Tomohito Tsuru¹, Yoshinori Shiihara², Takuya Iwashita³

The International Conference on Computational & Experimental Engineering and Sciences, Vol.32, No.2, pp. 1-1, 2024, DOI:10.32604/icces.2024.012770

Abstract Revealing the origin of the mechanical properties of metallic glasses (MG) is a long-standing problem. MGs respond to the external strain with the activation of collective atomic motion, but the triggers of such motions are not revealed yet, in contrast to the well-defined dislocations in crystals. In the present study we show that the change of atomic Von Mises stress is one of the key local parameters to indicate the stress response to a shear strain in metallic glass. Four random Cu50%Zr50% structures were prepared in first-principles molecular dynamics cooling process. Structures were then put… More >

Bosong Li¹, Jamie J. Kruzic^1,*

The International Conference on Computational & Experimental Engineering and Sciences, Vol.32, No.2, pp. 1-2, 2024, DOI:10.32604/icces.2024.011331

Abstract Additive manufacturing has made the fabrication of large-dimensioned bulk metallic glasses (BMGs) achievable; however, questions remain regarding how to control the processing parameters to obtain dense and fully amorphous BMGs with desirable mechanical properties. Here, laser powder bed fusion (LPBF) was used to produce dense and fully amorphous Zr_59.3Cu_28.8Nb_1.5Al_10.4 BMG samples from two different starting powders within a large processing window of laser powers and scanning speeds. X-ray diffraction (XRD) revealed that fully amorphous materials with high relative densities (>99%) were obtained when the LPBF energy density ranged from ~20 J/mm³ up to ~33 J/mm³ for coarse… More >

Yanhong Li^*, Bing Li, Xinhui Fan, Ke Yang, Xin Wang

FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.1, pp. 71-80, 2022, DOI:10.32604/fdmp.2022.017922 - 10 November 2021

Abstract In this study a Cu₄₃Zr₄₈Al₉ bulk metallic glass prepared by the copper mold casting method is considered. In recent years, Cu-Zr-Al systems like this have enjoyed widespread attention due to their high strength, high hardness, high corrosion resistance and low cost. Here samples of this substance are studied using DSC (Differential scanning calorimetry) to determine the effect of different test conditions (heating rate, sample mass, sample specific surface area and sample crystal phase) on the characteristic thermodynamic temperature of the bulk metallic glass. Experimental results show that almost all of the five characteristic thermodynamic temperatures More >

Yun Teng¹, Zhendong Sha^1,*

The International Conference on Computational & Experimental Engineering and Sciences, Vol.23, No.1, pp. 18-18, 2021, DOI:10.32604/icces.2021.08471

Abstract For all engineering materials, the flaws are introduced inevitably from fabrication, mechanical damage, and corrosion. These stress raisers always induce catastrophic failures and it is therefore of great importance to understand the effect of flaws on the mechanical properties of engineering materials. The effect of flaws on metallic glasses (MGs) is a debatable topic because many relevant works have reported notch strengthening, notch weakening and notch insensitivity for brittle MGs. The significant notch strengthening of MGs was attributed to the transition of failure mechanism, from catastrophic shear banding to ductile fracture. Here we investigate systematically… More >

Wen-Jay Lee^1,*, Yu-Chien Lo², Anchen Yang³, Kuanpeng Chen³, Nan-Yow Chen³

CMES-Computer Modeling in Engineering & Sciences, Vol.120, No.2, pp. 293-304, 2019, DOI:10.32604/cmes.2019.06620

Abstract Different thickness of amorphous/nanocrystalline multi-layered structure can be used to modulate the strength and ductility of the composite materials. In this work, molecular dynamics simulations were conducted to study the thickness effect of nanocrystalline layer on mechanical properties and deformation behavior of the Cu₆₄Zr₃₆/Cu multi-layer structure. The stress-strain relationship, local stress, local strain, and deformation mechanism are investigated. The results reveal that the change of thickness of the crystalline layer significantly affects the mechanical properties and deformation behavior. As the strain at the elastic region, the amorphous Cu₆₄Zr₃₆ layer dominates the mechanical behavior, leading the fact More >

Jin Ma¹, Jay C. Hanan¹, Ranga Komanduri¹, Hongbing Lu²

CMES-Computer Modeling in Engineering & Sciences, Vol.86, No.4, pp. 349-384, 2012, DOI:10.3970/cmes.2012.086.349

Abstract Amorphous metallic foams are an exciting class of materials for an array of high impact absorption applications, the mechanical behavior of which is only beginning to be characterized. To determine mechanical properties, guide processing, and engineer the microstructure for impact absorption, simulation of the mechanical properties is necessary as experimental determination alone can be expensive and time consuming. In this investigation, the material point method (MPM) with C1 continuous shape function is used to simulate the response of a bulk metallic glass (BMG) closed-cell foam (Pd42.5Cu30Ni7.5P20) under compression. The BMG foam was also tested experimentally… More >

Prakash Thamburaja

The International Conference on Computational & Experimental Engineering and Sciences, Vol.20, No.3, pp. 79-80, 2011, DOI:10.3970/icces.2011.020.079

Abstract Some recent experiments on sub-micron and nano-sized metallic glass specimens have shown that the shear localization process becomes more stable and less catastrophic when compared to the response exhibited by large sample sizes. This leads to the discovery that the shear localization process and fracture can be delayed by decreasing sample volume. In this work we develop a non-local and finite-deformation-based constitutive model using thermodynamic principles and the theory of micro-force balance to study the causes for the aforementioned observations. The constitutive model has also been implemented into a commercially-available finite-element program by writing a… More >

ZHIBIN LU, YUANLI XU, HANG SHAO, JIANGONG LI

The International Conference on Computational & Experimental Engineering and Sciences, Vol.16, No.2, pp. 63-64, 2011, DOI:10.3970/icces.2011.016.063

Abstract This paper reports the effects of strain rate and temperature on the steady state flow stress of metallic glasses. Based on the energy conservation between the applied mechanical work and the increased energy in metallic glasses at steady state flow, the steady state stress of metallic glasses was found to depend on difference in free volume between undeformed state and steady state of flow. The effects of strain rate (or temperature) on the steady state flow stress can be described by a linear relationship between the steady state flow stress and temperature (or logarithm of More >

R. Matsumoto¹, N. Miyazaki¹, M. Nakagaki²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.4, No.4, pp. 223-230, 2007, DOI:10.3970/icces.2007.004.223

Abstract The mechanical properties of amorphous metals and metallic glasses are remarkably changed by precipitated crystalline particles. In this paper, the effects of crystal particle size and volume fraction on the flow stress of the metallic glass are evaluated by molecular dynamics simulations. The investigated volume fraction ranges from 0% (metallic glass) to 100% (nanocrystalline metal), and the average particle diameter ranges from 1nm to 12nm. It is revealed that the dispersed particle effects on the flow stress are very small in the entire volume fraction range when the average particle diameter is smaller than 3 More >