Journal Published Online: 14 June 2018
Volume 7, Issue 2

Surface Topography Effects on the Fatigue Strength of Cast Aluminum Alloy AlSi8Cu3

CODEN: MPCACD

Abstract

This article investigates the effect of the cast surface topography on the fatigue strength of the cast aluminum alloy AlSi8Cu3, which is equivalent to EN AC-46200 and A380 according to ASTM. Fatigue tests utilizing small-scale specimens under bending at a load stress ratio of R = 0 reveal a significant influence of the cast surface layer, leading to a reduction of the nominal fatigue strength at ten million load cycles by about one half. Fracture surface analysis highlights that crack initiation occurs because of both surface roughness and micropores within the cast surface layer. A numerical simulation procedure to assess the influence of the surface roughness on the fatigue strength is presented. Thereby, a three-dimensional mesh of an optically scanned surface topography is set up and a local fatigue strength reduction factor is numerically computed based on the critical distance approach by Taylor. The results reveal that the presented method slightly overestimates the fatigue strength compared to the experiments; however, the determined values lead to a sound accordance if the scatter of the fatigue test data points is considered.

Author Information

Leitner, Martin
Christian Doppler Laboratory for Manufacturing Process Based Component Design, Institute of Mechanical Engineering, Leoben, Austria
Stoschka, Michael
Christian Doppler Laboratory for Manufacturing Process Based Component Design, Institute of Mechanical Engineering, Leoben, Austria
Fröschl, Jürgen
BMW Group, Department of Research, New Technologies, and Innovations, Garching, Germany
Wiebesiek, Jens
BMW Group, Department of Research, New Technologies, and Innovations, Garching, Germany
Pages: 17
Price: $25.00
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Details
Stock #: MPC20170127
ISSN: 2379-1365
DOI: 10.1520/MPC20170127