Advances in Fracture Toughness Test Methods for Ductile Materials in Low-Constraint Conditions

Zhu, Xian-Kui

doi:10.1016/j.proeng.2015.12.195

Cited by 11 publications

(7 citation statements)

References 50 publications

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“…The variation in the normalized maximum force, F max /A min 0 , and that of the normalized maximum extension, δ max /L 0 , with d G are shown in Figure 5c,d A series of optical images captured during the in situ tension tests of the single-edge notch specimens were directly used to extract crack-tip opening displacement, Δ. The crack-tip opening displacement is an effective parameter to characterize the extent of local deformation at the notch root [35][36][37]. The value of Δ is defined as the distance between the intercepts of two orthogonal lines originating from the notch tip and the opposite sides of the notch, as shown schematically in Figure 6a.…”

Section: Mechanical Responsementioning

confidence: 99%

Correlating Prior Austenite Grain Microstructure, Microscale Deformation and Fracture of Ultra-High Strength Martensitic Steels

Zheng

Ghassemi-Armaki

Hartwig

et al. 2021

Metals

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Herein, we correlate the prior austenite grain (PAG) microstructure to deformation and fracture mechanisms of an ultra-high strength martensitic steel. To this end, a low-carbon martensitic steel is subjected to five heat-treatments and the PAG microstructure in the material is reconstructed from the EBSD inverse pole figure maps of the martensitic microstructure. The deformation and fracture response of all heat-treated materials are characterized by in situ tension tests of dog-bone and single-edge notch specimens that allow us to capture both the macroscopic mechanical response and the evolution of microscopic strains via microscale digital image correlation. The experimental results, together with microstructure-based finite element analysis, are then used to elucidate the effect of the PAG microstructure on the mechanical response of the material. Our results show that the interaction between the heterogeneous deformation fields induced by the notch and the bimodal PAG size distribution leads to an increase in the propensity of shear deformation and degradation in the fracture response of the material with increasing heat-treatment temperature and time. Our results also suggest that achieving a unform distribution of fine grains is an effective way to enhance both the strength and fracture properties of this class of materials.

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Section: Mechanical Responsementioning

confidence: 99%

Correlating Prior Austenite Grain Microstructure, Microscale Deformation and Fracture of Ultra-High Strength Martensitic Steels

Zheng

Ghassemi-Armaki

Hartwig

et al. 2021

Metals

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“…[ 132–134 ] Alternatively, it has been proved that accurate measurement of the fracture toughness of a high‐strength thin sheet could be achieved through subsized geometry and side groove. [ 131,135–137 ] The ultrahigh strength and moderate fracture toughness of AHSS effectively reduce the qualification for thickness, and the side grooves help modify the crack tip triaxiality and mitigate the crack tunneling effect. [ 131,138,139 ] The authors have managed to measure the fracture toughness values of two types of PHS (1500 and 2000 MPa strength grade) by applying the side groove strategy to subsidized C(T) specimens.…”

Section: Test Methods For He Evaluation In Phsmentioning

confidence: 99%

Hydrogen Embrittlement Evaluation and Prediction in Press‐Hardened Steels

Cao

Wang

Ngiam

et al. 2023

steel research int.

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The application of press-hardened steels (PHSs) in automotive body-in-white components using the hot-stamping technique is growing thanks to its impressive strength and formability. Unfortunately, hydrogen embrittlement (HE), an issue that generally exists in high-strength steels, impedes the PHSs rising application trend by causing catastrophic mechanical property degradation. Thus, detailed evaluation and prediction of HE risk throughout PHSs manufacture and service condition are necessary. This study highlights techniques to characterize the hydrogen content and distribution, techniques to evaluate HE susceptibility, and potential models to simulate the in-service performance of PHS. The survey of existing studies has revealed the gaps between laboratory measurement and industry application, including but not limited to 1) the accelerated experiment-induced discrepancies against real-life applications, 2) a selection of the appropriate HE indicators, 3) an accurate risk prediction model, and 4) efficient feedback to the industry based on both experimental and simulated results. Based on the review, future studies are expected to establish a conclusive HE evaluation standard for PHS.

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“…The crack tip constraint significantly influences the measured fracture toughness and focus is typically on high constraint (plane strain) values. In case the crack tip constraint is low, dedicated specimens and procedures exist; subject of a comprehensive review (Zhu, 2015, Ruggieri, 2017. Comparative studies of available test methods using single edge notch tension specimens together with crack tip opening displacement-and J-integral values have been presented (Park et al, 2017, Zhu, 2017.…”

Section: Fracture Propertiesmentioning

confidence: 99%

Report of Committee III.2: Fatigue and fracture

2015

Ships and Offshore Structures XIX

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Advances in Fracture Toughness Test Methods for Ductile Materials in Low-Constraint Conditions

Cited by 11 publications

References 50 publications

Correlating Prior Austenite Grain Microstructure, Microscale Deformation and Fracture of Ultra-High Strength Martensitic Steels

Correlating Prior Austenite Grain Microstructure, Microscale Deformation and Fracture of Ultra-High Strength Martensitic Steels

Hydrogen Embrittlement Evaluation and Prediction in Press‐Hardened Steels

Report of Committee III.2: Fatigue and fracture

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