Abstract
This study investigates the influence of pre-corrosion damage on the fatigue behavior
of AlSi10MgMn high-pressure die-cast specimens, using the statistical distribution of corrosion
depths. The analysis is conducted on two different surface conditions: an unmachined rough
surface (Ra = 5.05 μm) and a machined, polished surface (Ra = 0.25 μm). For the unmachined
specimens, the corrosive damage manifests as homogeneously spread localized corrosion, whereas
the polished specimens exhibit less uniform but deeper corrosion. The average corrosion depth of the
polished specimens is found to be slightly higher (313 μm compared to 267 μm) with a broader depth
distribution. Specimens are tested under a constant bending load amplitude in laboratory conditions
at a stress ratio of R = 0 until fracture. A fracture mechanics-based methodology is developed
to assess the remaining fatigue life of corroded specimens, utilizing short and long crack fracture
mechanical parameters derived from SENB specimens. This model incorporates a thickness reduction
of the critical specimen cross-section based on the corrosion depth distribution and combines it with
a small initial crack of the intrinsic defect size (ae f f = 14 μm). Regardless of the surface condition,
using the most frequent corrosion depth for thickness reduction provides a good estimate of the
long-life fatigue strength, while using the 90th percentile depth allows for a conservative assessment.
of AlSi10MgMn high-pressure die-cast specimens, using the statistical distribution of corrosion
depths. The analysis is conducted on two different surface conditions: an unmachined rough
surface (Ra = 5.05 μm) and a machined, polished surface (Ra = 0.25 μm). For the unmachined
specimens, the corrosive damage manifests as homogeneously spread localized corrosion, whereas
the polished specimens exhibit less uniform but deeper corrosion. The average corrosion depth of the
polished specimens is found to be slightly higher (313 μm compared to 267 μm) with a broader depth
distribution. Specimens are tested under a constant bending load amplitude in laboratory conditions
at a stress ratio of R = 0 until fracture. A fracture mechanics-based methodology is developed
to assess the remaining fatigue life of corroded specimens, utilizing short and long crack fracture
mechanical parameters derived from SENB specimens. This model incorporates a thickness reduction
of the critical specimen cross-section based on the corrosion depth distribution and combines it with
a small initial crack of the intrinsic defect size (ae f f = 14 μm). Regardless of the surface condition,
using the most frequent corrosion depth for thickness reduction provides a good estimate of the
long-life fatigue strength, while using the 90th percentile depth allows for a conservative assessment.
Original language | English |
---|---|
Article number | 1135 |
Number of pages | 20 |
Journal | Metals : open access journal |
Volume | 14.2024 |
Issue number | 10 |
DOIs | |
Publication status | Published - 5 Oct 2024 |