Fatigue and fractures of RG7 bronze after cyclic torsion and bending. (March 2023)

• Record Type: Journal Article
• Authors: Małecka, Joanna; Łagoda, Tadeusz
• Is Part Of: International journal of fatigue. Volume 168(2023)
• Publication Date: 2023-03
• Subjects: Fatigue fracture -- Bending and torsion -- Fracture plane; Materials -- Fatigue -- Periodicals; Materials -- Fatigue; Periodicals; 620.1122
• DOI: 10.1016/j.ijfatigue.2022.107475
• Languages: English
• ISSNs: 0142-1123

Abstract

Highlights: Determine the stresses according to the model of an elasto-plastic body for bending and torsion loading. Bronze RG7, incorporation of the plasticity results in a reduction of the determined stresses. The morphology of fracture surface of investigated bronze display the multi crack initiation origins, which are shallow surface damages. Bending and torsion the cracks always occurred on one side only, which is the consequence of the very high plasticity of the material. Abstract: The paper presents the results of fatigue tests of RG7 bronze in the conditions of cyclic bending (τa = 0), cyclic torsion (σa = 0) and the combination of cyclic bending and torsion (τa = σa and τa = 0.5 σa ) performed on a bending-torsion test stand. In this paper, a model for incorporating elasto-plastic deformation in bending-torsion combinations was proposed and used to describe the fatigue of the tested bronze. Causes of damage were determined by microscopic observations. The fracture surface observation was performed using a Scanning Electron Microscope Tescan Vega 4, the component investigation of the fracture surface was performed by Energy Dispersive X-ray Spectroscopy. Observations of fatigue fractures were carried out for one specimen selected for analysis for each combination: with a lifetime of approximately 100.000–500.000 cycles. Based on the observations, the fatigue fractures were found to be similar, indicating that the nature of the fatigue process in these cases was not qualitatively different.