The objective of the present study was to investigate the effect of surface hardening by shotpeening (SP) on fatigue properties of high-strength aluminium alloy 7075-T651. The paper describes the effects of SP treatment by presenting analyses of surface roughness measurement, microhardness profiles, microstructure changes, residual stresses and material bending fatigue resistance. The obtained results show a favourable influence of SP treatment on fatigue properties as induced compressive residual stresses and hardened surface layer retarded the initiation of fatigue cracks. SP treatment nearly doubled the cycles to failure at the higher applied stresses when compared to the untreated specimens. The fatigue limit of the SP-treated specimens increased to 218 MPa at 10 7 cycles. The experimental data confirmed an increase of fatigue strength after SP treatment due to the compressive residual stress ability to influence fatigue crack nucleation. Increased resistance to plastic deformation and the residual stress profiles provided a corresponding fatigue crack closure.
The objective of the present study was to investigate the effect of surface hardening by shotpeening (SP) on fatigue properties of high-strength aluminium alloy 7075-T651. The paper describes the effects of SP treatment by presenting analyses of surface roughness measurement, microhardness profiles, microstructure changes, residual stresses and material bending fatigue resistance. The obtained results show a favourable influence of SP treatment on fatigue properties as induced compressive residual stresses and hardened surface layer retarded the initiation of fatigue cracks. SP treatment nearly doubled the cycles to failure at the higher applied stresses when compared to the untreated specimens. The fatigue limit of the SP-treated specimens increased to 218 MPa at 10 7 cycles. The experimental data confirmed an increase of fatigue strength after SP treatment due to the compressive residual stress ability to influence fatigue crack nucleation. Increased resistance to plastic deformation and the residual stress profiles provided a corresponding fatigue crack closure.
Shot peening has been a very important and well-known surface cold-hardening process applicable to various machine parts and tool surfaces for quite a long time since it improves fatigue strength and corrosion resistance of stressed surfaces. Hardening by shot peening provides, because of plastic deformation, an increase in hardness and induces compressive residual stresses in the thin surface layer, which reduces material fatigue and prevents the generation and propagation of cracks. The present paper reports of results of shot peening hardening of specimens made of 7075-T651 aluminium. They were surface-hardened by steel shots M170 with Almen hardening intensity of 8A and 12A respectively and by glass beads GP165 with Almen hardening intensity of 12A. The steel shots and glass beads had the same diameter but differed considerably in hardness and density. The surface condition after shot peening processing was assessed in terms of surface integrity, which establishes a relation between processing conditions and roughness state and hardened-layer depth supported by an analysis of residual-stress variations.
Pitting corrosion has a major influence on aging of structural elements made of high-strength aluminium alloys as corrosion pits lead to much earlier fatigue crack initiation under tensile dynamic loading. In order to improve material resistance to corrosion fatigue, it is necessary to reduce pit-tip stresses in the corroded pits areas. Shot peening (SP) is an important and well-known cold working process, having been used in industrial applications for a long time. Shot peening as intense plastic deformation in the thin surface layer affects cold surface hardening by primary inducing favorable residual compressive stresses. It is used in order to increase fatigue strength in operation and to improve fatigue resistance of precorroded material. The paper deals with the surface integrity of shot-peened high-strength 7075-T651 aluminium alloy. The paper describes the effects of SP treatment by presenting analyses of surface roughness measurement, residual stresses, material bending fatigue resistance, fractographic analysis of fatigued specimens, and electrochemical potentiodynamic testing.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2025 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.