Hardness, toughness, brittleness and cracking systems in an iron-based bulk metallic glass by indentation

Though extensively studied, hardness, defined as the resistance of a material to deformation, still remains a challenging issue for a formal theoretical description due to its inherent mechanical complexity. The widely applied Teter's empirical correlation between hardness and shear modulus has been considered to be not always valid for a large variety of materials. Here, inspired by the classical work on Pugh's modulus ratio, we develop a theoretical model which establishes a robust correlation between hardness and elasticity for a wide class of materials, including bulk metallic glasses, with results in very good agreement with experiment. The simplified form of our model also provides an unambiguous theoretical evidence for Teter's empirical correlation.

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“…(6) is also valid for BMGs. Using the experimental shear modulus G = 38.6 (36.6) GPa [17] for Pd 40 [18]. As illustrated in the inset of Fig.…”

Section: Model and Resultsmentioning

confidence: 99%

Modeling hardness of polycrystalline materials and bulk metallic glasses

et al. 2011

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“…For a given milling time, the hardness of the hot pressed samples is higher than those of the hot pressed and hot extruded material. This can be explained by the smaller particle sizes (15 ± 12 m) and more homogeneous distribution of the hard Fe-based glassy particles throughout the hot pressed microstructure than those consolidated by hot extrusion (22 ± 10 µm) [38]. A maximum average hardness value of 155 HV was measured for the 50-h milled and hot pressed sample, which is compatible with its microstructure, presenting a uniform distribution of fine glassy particles without significant clustering (Figure 4d).…”

Section: Processing and Characterization Of The Composite Powdersmentioning

confidence: 99%

Effect of Milling Time and the Consolidation Process on the Properties of Al Matrix Composites Reinforced with Fe-Based Glassy Particles

Balcı

Prashanth

Scudino

et al. 2015

Metals

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Al matrix composites reinforced with 40 vol% Fe50.1Co35.1Nb7.7B4.3Si2.8 glassy particles have been produced by powder metallurgy, and their microstructure and mechanical properties have been investigated in detail. Different processing routes (hot pressing and hot extrusion) are used in order to consolidate the composite powders. The homogeneous distribution of the glassy reinforcement in the Al matrix and the decrease of the particle size are obtained through ball milling. This has a positive effect on the hardness and strength of the composites. Mechanical tests show that the hardness of the hot pressed samples increases from 51-155 HV, and the strength rises from 220-630 MPa by extending the milling time from 1-50 h. The use of hot extrusion after hot pressing reduces OPEN ACCESSMetals 2015, 5 670 both the strength and hardness of the composites: however, it enhances the plastic deformation significantly.

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“…Fracture toughness of Fe-based metallic glasses has been measured with indentation [15][16][17], whereas notch toughness testing has been completed on samples with nonstandard geometry [6,18,19]. Despite being most popular for samples with limited size, an indentation fracture test is not reliable for brittle materials because of the ill-defined crack arrest state that complicates analysis when compared to the rapid through-crack propagation of standardized tests [20,21].…”

Section: Introductionmentioning

confidence: 99%

Bulk Mechanical Properties Testing of Metallic Marginal Glass Formers

Phan

Kelly

Kassner

et al. 2016

Journal of Metallurgy

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We developed a unique three-point bend testing apparatus to measure bulk mechanical properties of a model metallic glass alloy (SAM2X5 with nominal composition Fe 49.7 Cr 17.1 Mn 1.9 Mo 7.4 W 1.6 B 15.2 C 3.8 Si 2.4 ) prepared by spark plasma sintering. The relatively large sample sizes in the present work allowed for the preparation of test specimens with a macroscale cross section (in the millimeter range) with well-controlled sample dimensions closer to standardized tests. Wire saw cutting allowed for a relatively sharp notch radius (3x smaller than previous studies) and minimal sample damage. We determined that Young's modulus and notch fracture toughness measured by our three-point bending apparatus are 230 GPa and 4.9 MPa⋅m 1/2 . Also, Vickers indentation and flexure testing provided consistent results for Young's modulus. Indentation fracture toughness measured by Vickers indentation produced values at least 50% lower than by flexure. The microscale mechanical properties testing technique presented in this work and subsequent analyses are applicable to specimens of other compositions or ones prepared by other methods.

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Hardness, toughness, brittleness and cracking systems in an iron-based bulk metallic glass by indentation

Cited by 107 publications

References 39 publications

Modeling hardness of polycrystalline materials and bulk metallic glasses

Modeling hardness of polycrystalline materials and bulk metallic glasses

Effect of Milling Time and the Consolidation Process on the Properties of Al Matrix Composites Reinforced with Fe-Based Glassy Particles

Bulk Mechanical Properties Testing of Metallic Marginal Glass Formers

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