Evaluation of fracture toughness using small notched specimens

Lee, Baik-Woo; Jang, Jae-il; Kwon, Dongil

doi:10.1016/s0921-5093(01)01804-4

Cited by 24 publications

(13 citation statements)

References 8 publications

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“…Therefore, as suggested in previous articles of the authors, an apparent fracture toughness K app was reported . This value was generally higher than K IC measured according to ASTM E399, i.e., with a crack tip radius close to zero …”

Section: Methodssupporting

confidence: 49%

Fracture Toughness of a Hot Work Tool Steel Fabricated by Laser‐Powder Bed Fusion Additive Manufacturing

Pellizzari

Furlani

Deirmina

et al. 2019

steel research int.

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The fracture toughness of AISI H13 tool steel, additively manufactured by laser powder bed fusion (L-PBF) technique, is studied. The influence of the building direction on fracture toughness is investigated on small notched bending samples heat treated according to two different thermal cycles, namely, quenching and tempering (QT) and only tempering (T). The notch is electrodischarge machined parallel (P || ), perpendicular (P ⊥ ), and longitudinal (L) to the building direction. Both heat treatments, even if to a different extent, delete the as-built (AB) microstructure, producing secondary carbides precipitation in the martensitic matrix. The microstructure of the directly tempered parts is finer than the quenched and tempered ones. The fracture toughness increases moving from P ⊥ to P || . The T samples show a higher apparent fracture toughness in the P || , despite the higher hardness. Secondary cracks formation allows reducing the main crack opening driving force increasing the fracture toughness in P || samples. This effect is more pronounced in T samples where the stronger precipitation of carbides at the prior melt boundaries promotes secondary cracks. Moreover, in P || samples the laser tracks act as barriers to crack propagation and as stress dissipators.

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Section: Methodssupporting

confidence: 49%

Fracture Toughness of a Hot Work Tool Steel Fabricated by Laser‐Powder Bed Fusion Additive Manufacturing

Pellizzari

Furlani

Deirmina

et al. 2019

steel research int.

View full text Add to dashboard Cite

show abstract

“…Additionally, the notch root radius ( ρ ) of specimen would affect the toughness through the variation of the stress field around the notch tip . For the Charpy impact test, the plastic zone radius ahead of the notch root is much larger than the prior austenite grain size under the effect of high‐rate stress, as displayed (yellow curve) in Figure b, which has been verified by the previous experimental study and finite element analysis . Hence, the stress around the notch tip can easily reach the critical fracture strength, resulting in the crack initiation.…”

Section: Discussionmentioning

confidence: 51%

The Relationship between Strength and Toughness in Tempered Steel: Trade‐Off or Invariable?

Duan

Zhang

et al. 2019

Adv Eng Mater

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Two different types of strength-toughness relations are investigated in tempered steel (tempered at 25-420 C). It is found that there is a trade-off relation between strength-fracture toughness and becomes invariable relation between strength-impact toughness. The effect of microstructure on the materials toughness is related to the manner of energy consumption, which should be attributed to the notch root radius of the specimen. The coarse carbides and dislocation density inside the martensite lath have distinct effects on the energy for crack initiation (impact toughness) and crack growth (fracture toughness). Additionally, the mechanism of coarse carbides on the tempered martensite embrittlement is elaborated deeply.

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“…Lewandowski compared the increase in BMG apparent toughness with increasing notch root radius to steels, aluminum alloys, and titanium alloys (Figure ) and found most crystalline alloys had only a modest increase in K Q , with the most extreme showing a factor of two increase in K Q for a notch root radius of ≈110 μm . Furthermore, often crystalline materials have a critical notch radius, ρ 0 , below which the notch toughness is equal to the pre‐cracked toughness . For metals the critical radius is typically several hundreds of micrometers for various metal alloys, while for brittle ceramics ρ 0 ≈ 10–30 μm is typical .…”

Section: Damage Tolerance Of Bulk Metallic Glassesmentioning

confidence: 99%

“…Furthermore, often crystalline materials have a critical notch radius, ρ 0 , below which the notch toughness is equal to the pre‐cracked toughness . For metals the critical radius is typically several hundreds of micrometers for various metal alloys, while for brittle ceramics ρ 0 ≈ 10–30 μm is typical . In contrast to crystalline materials, a very strong notch effect has been observed to persist for BMGs even with very sharp notch radii.…”

Section: Damage Tolerance Of Bulk Metallic Glassesmentioning

confidence: 99%

Bulk Metallic Glasses as Structural Materials: A Review

Kruzic

2016

Adv Eng Mater

231

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Bulk metallic glasses (BMGs) can exhibit excellent combinations of strength and fracture toughness that cannot be achieved by traditional metals, making them attractive for load bearing, mechanical engineering applications. Furthermore, recent research on BMGs has shown that many early perceived shortcomings, such as apparent brittleness or poor fatigue resistance, are not as big of a problem as once thought. The purpose of this paper is to review some of the unique mechanical characteristics of BMGs along with some of the strategies that may be used to improve or exploit their characteristics so that BMGs may be used as structural materials in engineering applications.

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Evaluation of fracture toughness using small notched specimens

Cited by 24 publications

References 8 publications

Fracture Toughness of a Hot Work Tool Steel Fabricated by Laser‐Powder Bed Fusion Additive Manufacturing

Fracture Toughness of a Hot Work Tool Steel Fabricated by Laser‐Powder Bed Fusion Additive Manufacturing

The Relationship between Strength and Toughness in Tempered Steel: Trade‐Off or Invariable?

Bulk Metallic Glasses as Structural Materials: A Review

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