Date of Award

2025-12-01

Degree Name

Master of Science

Department

Mechanical Engineering

Advisor(s)

Francisco Medina

Abstract

Laser Powder Bed Fusion (LBPF) AlSi10Mg is used in the aerospace and automotive industries for its refined microstructure and ductility compared to cast alloys. However, LPBF processes can inherently lead to defects that may act as fatigue crack initiators, such as lack of fusion, balling, and keyhole porosity. This work focuses on the analysis of high-cycle fatigue (HCF) endurance of AlSi10Mg under expected service conditions. For this study, AlSi10Mg specimens were printed on an EOS M290 LPBF system and heat-treated by stress relief (SR1), Hot Isostatic Pressing (HIP), and Hot Isostatic Pressing + T6 (HIP+T6), as per ASTM 3318. Specimens were subsequently artificially aged at 177°C for 0, 10, 100, and 1000 hours. HCF, in accordance with E466, was conducted to determine the endurance of the specimens at various stress levels. Results revealed a stark difference in the fatigue life between the two stress levels, with SR1 consistently high at the low stress level and exhibiting variations due to defects. In contrast, HIP and HIP+T6 exhibited a steady decline with increasing aging parameters. Before fatigue testing, the samples were CT-scanned, revealing a decrease in porosity during aging. SR1, the least affected by aging, had a porosity of 0.12% at 0 hours, increasing to 0.14% at 1000 hours. HIP+T6 started at 0.01% and dropped to 0.00% over 1000 aging hours.

Language

en

Provenance

Received from ProQuest

File Size

136 p.

File Format

application/pdf

Rights Holder

Luis Alfredo Barrera

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