Finite fracture mechanics predictions on the apparent fracture toughness of as-quenched Charpy V-type AISI 4340 steel specimens
| Autor: | Donato Firrao, Alberto Giuseppe Sapora |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Quenching
Critical distance Materials science Mechanical Engineering Metallurgy Charpy impact test Fracture mechanics 02 engineering and technology 021001 nanoscience & nanotechnology Strength of materials Stress (mechanics) 020303 mechanical engineering & transports Fracture toughness 0203 mechanical engineering Mechanics of Materials Ultimate tensile strength General Materials Science Composite material 0210 nano-technology |
| Zdroj: | Fatigue & Fracture of Engineering Materials & Structures. 40:949-958 |
| ISSN: | 8756-758X |
| Popis: | Quenching AISI 4340 steel from 1200 °C leads to much higher fracture toughness in the as-quenched state than by conventional austenitizing at 870 °C. However, the increase is limited to fracture toughness tests, because Charpy V impact/slow bend tests do not show any betterment due to high-temperature austenitizing. Different explanations of these contradicting results have been proposed since the beginning of the 1970s. In the present paper, this puzzling phenomenon will be revisited through the coupled stress and energy criterion in the framework of finite fracture mechanics. The approach involves two material parameters, namely the tensile strength and the fracture toughness, and a critical distance (or finite crack advance), which results to be a structural property. The connection between the critical distance, the microstructure characteristic (i.e. the grain size) and the effective radius involved by other models proposed in the past will be outlined, providing an interesting overview on the studies carried out during the last four decades. |
| Databáze: | OpenAIRE |
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