Issues »  Volume 46, Issue 10

Mechanical Stability and Brittleness of Metals and Alloys. Pt. 3. Physical-Mechanical Concept of Strength and Destruction of Metals and Alloys

Yu. Ya. Meshkov and H. P. Zimina

G. V. Kurdyumov Institute for Metal Physics, NAS of Ukraine, 36 Academician Vernadsky Blvd., UA-03142 Kyiv, Ukraine

Received: 27.03.2024; final version - 06.05.2024. Download: PDF

This work offers the fundamentals of a new approach to the nature of strength and failure of metallic materials under the conditions of stress–strain state (SSS) of a general type, which occurs within the local zones of non-uniform force fields (NFF) due to the stress raisers (SR). Basic foundation of the physical and mechanical concept of structural strength of metals and alloys, σNF, is considered based on the comparison of the proposed strength margin (SM) parameter for two cases: ΔS for uniform force fields (UFF) and ΔσN for non-uniform force fields (NFF) near the SR. Exhaustion of each type of SM means a transition to brittle fracture, which, for SM at NFF, manifests itself in a steep fall in structural strength: σNF < σ0.2. Exhaustion of strength margins ΔS and ΔσN may occur due to both physical (alloy structure, temperature conditions) factors and purely mechanical ones (type of SSS, SR), which cause embrittlement of metals. A special mechanical characteristic is proposed—break resistance br (basic one for the uniform SSS) and brN (structural one for the non-uniform SSS), the ratio between which governs the regularities of influence of strength σ0.2 (conditional yield strength) and strength margin ΔS on such manifestations of brittleness of metals as cold brittleness, when the temperature is decreased, or ‘mechanical brittleness’ due to the SR at room temperature TК. Examples of the application of parameters ΔS, ΔσN and br, brN are given for the analysis of experimental evidence published by various authors. A conclusion is made about the effectiveness of using structural strength parameters in investigation of the nature of brittleness and embrittlement of metal alloys caused by their extra hardening, the temperature decrease, or the SR effect (cracks, etc.).

Key words: steel, strength, strength margin, break resistance, brittle fracture, cold resistance, structural strength, mechanical stability, uniform and non-uniform force fields (UFF, NFF).

URL: https://mfint.imp.kiev.ua/en/abstract/v46/i10/1031.html

DOI: https://doi.org/10.15407/mfint.46.10.1031

PACS: 46.50.+a, 62.20.fk, 62.20.fq, 62.20.M-, 62.20.mj, 62.20.mm, 62.20.mt

Citation: Yu. Ya. Meshkov and H. P. Zimina, Mechanical Stability and Brittleness of Metals and Alloys. Pt. 3. Physical-Mechanical Concept of Strength and Destruction of Metals and Alloys, Metallofiz. Noveishie Tekhnol., 46, No. 10: 1031—1050 (2024) (in Ukrainian)

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