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ML00183 - Dec.2022

Ductile Behavior of an Aluminum Wheel

Low magnification view of the WHEEL 1 fracture surface. The thickness of the wheel in this position (flat and paralell to the wheel face) is about 2.5 mm. The aspect of the fracture is similar all through the fracture perimeter, including the region where the fracture propagation changes the direction.

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Low magnification view of the WHEEL 1 surface. The thickness of the wheel in this position (flat and paralell to the wheel face) is about 2.5 mm. The aspect of the is similar all through the perimeter, including the region where the propagation changes the direction.
M

Material

Aluminum Silicon Magnesium
  • UNS A03560
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Description

The front wheels 17 x 7J of a passenger vehicle broke during a car accident on a road. One of the wheels fractured in two parts and the other showed a circumferential , both with micromechanism, predominantly by . The same aspect was identified in the of the tensile specimen. Although there are small and the of the wheel presents brittle particles, the material behaved in a ductile manner even with the strong impact, as expected.

C

Chemistry (% in weight)

Wheel Alloy Al Si 7

7.05Si; 0.08Fe; 0.01Cu; 0.006Mn; 0.20Mg; 0.10Ti.

Associated Images
Front wheel 17 x 7J of a passenger vehicle (identified as WHEEL 1) that broke during a car accident on a road.
1645
VIEW
ML00183 / Dec.2022
Ductile Behavior of an Aluminum Wheel
M - Aluminum Silicon MagnesiumP - CastingAp - AutomotiveCd - Ductile Behavior
Cm - Aspect Before AnalysisDf - General View
Front wheel 17 x 7J of a passenger vehicle (identified as WHEEL 2) that cracked exactly in the same location that the other front wheel broke.
91
VIEW
ML00183 / Dec.2022
Ductile Behavior of an Aluminum Wheel
M - Aluminum Silicon MagnesiumP - CastingAp - AutomotiveCd - Ductile Behavior
Cm - Aspect Before AnalysisDf - General View
Aspect of the two wheels before disassembling the tires.
75
VIEW
ML00183 / Dec.2022
Ductile Behavior of an Aluminum Wheel
M - Aluminum Silicon MagnesiumP - CastingAp - AutomotiveCd - Ductile Behavior
Cm - Aspect Before AnalysisDf - General View
Detail of the fracture in the WHEEL 1, changing direction of propagation.
71
VIEW
ML00183 / Dec.2022
Ductile Behavior of an Aluminum Wheel
M - Aluminum Silicon MagnesiumP - CastingAp - AutomotiveCd - Ductile Behavior
Cm - Aspect Before AnalysisDf - Fracture
Detail of the crack in the WHEEL 2, changing direction of propagation exactly like the other whel.
66
VIEW
ML00183 / Dec.2022
Ductile Behavior of an Aluminum Wheel
M - Aluminum Silicon MagnesiumP - CastingAp - AutomotiveCd - Ductile Behavior
Cm - Aspect Before AnalysisDf - Cracking
Low magnification view of the WHEEL 1 fracture surface. The thickness of the wheel in this position (flat and paralell to the wheel face) is about 2.5 mm. The aspect of the fracture is similar all through the fracture perimeter, including the region where the fracture propagation changes the direction.
66
VIEW
ML00183 / Dec.2022
Ductile Behavior of an Aluminum Wheel
M - Aluminum Silicon MagnesiumP - CastingAp - AutomotiveCd - Ductile Behavior
Cm - Fractography by SEMDf - General View
WHEEL 1 fracture detail showing a small shrinkage in the left side of the photo and dimples in the right side of the photo.
73
VIEW
ML00183 / Dec.2022
Ductile Behavior of an Aluminum Wheel
M - Aluminum Silicon MagnesiumP - CastingAp - AutomotiveCd - Ductile Behavior
Cm - Fractography by SEMDf - Ductile Fracture
WHEEL 1 fracture detail showing predominantly dimples as the fracture micromechanism.
74
VIEW
ML00183 / Dec.2022
Ductile Behavior of an Aluminum Wheel
M - Aluminum Silicon MagnesiumP - CastingAp - AutomotiveCd - Ductile Behavior
Cm - Fracture Surface AspectDf - Ductile Fracture
WHEEL 1 fracture detail showing small regions of shearing.
67
VIEW
ML00183 / Dec.2022
Ductile Behavior of an Aluminum Wheel
M - Aluminum Silicon MagnesiumP - CastingAp - AutomotiveCd - Ductile Behavior
Cm - Fractography by SEMDf - Elongated Dimples
WHEEL 1 fracture detail showing small regions with smooth aspect, and brittle microcracks. But predominantly the micromechanism is by dimples.
70
VIEW
ML00183 / Dec.2022
Ductile Behavior of an Aluminum Wheel
M - Aluminum Silicon MagnesiumP - CastingAp - AutomotiveCd - Ductile Behavior
Cm - Fractography by SEMDf - Cracks
WHEEL 1 fracture detail of the brittle microcracks. The analysis of the material microstructure showed that these microcracks are associated to iron rich phases.
68
VIEW
ML00183 / Dec.2022
Ductile Behavior of an Aluminum Wheel
M - Aluminum Silicon MagnesiumP - CastingAp - AutomotiveCd - Ductile Behavior
Cm - Fractography by SEMDf - Cracks
Macrography of a radial section of the WHEEL 1. The fracture occurred in the cylindrical wheel outer edge, the rim, and the thickness of the part in the fracture location varied from 2.5 mm to 4 mm.
62
VIEW
ML00183 / Dec.2022
Ductile Behavior of an Aluminum Wheel
M - Aluminum Silicon MagnesiumP - CastingAp - AutomotiveCd - Ductile Behavior
Cm - Keller Etched MacroDf - Radial Section
Macro view of a fractured wheel spoke section showing an irregular, shear-lip fracture edge consistent with ductile overload.
52
VIEW
ML00183 / Dec.2022
Ductile Behavior of an Aluminum Wheel
M - Aluminum Silicon MagnesiumP - CastingAp - AutomotiveCd - Ductile Behavior
Cm - Keller Etched MacroDf - Radial Section
The wheel microstructure changed a little depending the thickness. In the region of WHEEL 1 fracture and WHEEL 2 cracking, it presented an alpha matrix with a networklike precipitates interdendritic.
46
VIEW
ML00183 / Dec.2022
Ductile Behavior of an Aluminum Wheel
M - Aluminum Silicon MagnesiumP - CastingAp - AutomotiveCd - Ductile Behavior
Cm - Keller Etched Micrography by OMDf - Hypoeutetic
Detail of the alpha matrix with an eutectic networklike precipitates, interdendritic. Presence of acicular iron rich phases (dark gray).
51
VIEW
ML00183 / Dec.2022
Ductile Behavior of an Aluminum Wheel
M - Aluminum Silicon MagnesiumP - CastingAp - AutomotiveCd - Ductile Behavior
Cm - Keller Etched Micrography by OMDf - Networklike precipitates
Low magnification view of the broken tensile specimen fracture surface. The same macroscopic aspect as the WHEEL 1 fracture surface.
48
VIEW
ML00183 / Dec.2022
Ductile Behavior of an Aluminum Wheel
M - Aluminum Silicon MagnesiumP - CastingAp - AutomotiveCd - Ductile Behavior
Cm - Testpiece aspectDf - Ductile Fracture
Detail of the broken tensile specimen fracture surface. Predominantly dimples.
45
VIEW
ML00183 / Dec.2022
Ductile Behavior of an Aluminum Wheel
M - Aluminum Silicon MagnesiumP - CastingAp - AutomotiveCd - Ductile Behavior
Cm - Testpiece aspectDf - Dimples
Tensile specimen fracture surface showing a small shrinkage and dimples, exactly as the WHEEL 1 fracture appearance (figure 7).
36
VIEW
ML00183 / Dec.2022
Ductile Behavior of an Aluminum Wheel
M - Aluminum Silicon MagnesiumP - CastingAp - AutomotiveCd - Ductile Behavior
Cm - Testpiece aspectDf - Fracture
In the broken specimen fracture surface there are also regions of small cracks, that appear secondary, but that did not propagate. The predominantly mechanism is dimples.
38
VIEW
ML00183 / Dec.2022
Ductile Behavior of an Aluminum Wheel
M - Aluminum Silicon MagnesiumP - CastingAp - AutomotiveCd - Ductile Behavior
Cm - Testpiece aspectDf - Cracks
Detail of the small cracks in a brittle phase, analyzed by EDS as rich in iron.
38
VIEW
ML00183 / Dec.2022
Ductile Behavior of an Aluminum Wheel
M - Aluminum Silicon MagnesiumP - CastingAp - AutomotiveCd - Ductile Behavior
Cm - Testpiece aspectDf - Brittle Cracks
Micrography transverse to the fracture surface of the WHEEL 1. The fracture is in the up right position of the photo and it can be observed a secondary cracking following the interdendritic precipitates.
33
VIEW
ML00183 / Dec.2022
Ductile Behavior of an Aluminum Wheel
M - Aluminum Silicon MagnesiumP - CastingAp - AutomotiveCd - Ductile Behavior
Cm - Keller Etched Micrography by OMDf - Radial Section
Micrographic detail of the secondary crack from the fracture surface of the WHEEL 1, following the interdendritic precipitates.
36
VIEW
ML00183 / Dec.2022
Ductile Behavior of an Aluminum Wheel
M - Aluminum Silicon MagnesiumP - CastingAp - AutomotiveCd - Ductile Behavior
Cm - Keller Etched Micrography by OMDf - Fracture
Macrography transverse to the fracture surface of the WHEEL 1. The fracture is in the top of the image.
35
VIEW
ML00183 / Dec.2022
Ductile Behavior of an Aluminum Wheel
M - Aluminum Silicon MagnesiumP - CastingAp - AutomotiveCd - Ductile Behavior
Cm - Keller Etched MacroDf - Fracture
Low magnification micrography transverse to the fracture surface of the WHEEL 1. The fracture is in the top of the image and there is a void (shrinkage) not connected to the fracture .
34
VIEW
ML00183 / Dec.2022
Ductile Behavior of an Aluminum Wheel
M - Aluminum Silicon MagnesiumP - CastingAp - AutomotiveCd - Ductile Behavior
Cm - Micrography by SEMDf - Fracture
Detail of the micrography transverse to the fracture surface of the WHEEL 1, close to the void, that is a region of impurities. The iron rich particles are brittle and with several microcracks, that did not propagate during the impact.
27
VIEW
ML00183 / Dec.2022
Ductile Behavior of an Aluminum Wheel
M - Aluminum Silicon MagnesiumP - CastingAp - AutomotiveCd - Ductile Behavior
Cm - Micrography by SEMDf - Cracks
Detail of the brittle iron rich particles with several microcracks, that did not propagate during the impact that lead to the fracture.
26
VIEW
ML00183 / Dec.2022
Ductile Behavior of an Aluminum Wheel
M - Aluminum Silicon MagnesiumP - CastingAp - AutomotiveCd - Ductile Behavior
Cm - Micrography by SEMDf - Brittle Cracks
Detail of the brittle iron rich particles with several microcracks, that did not propagate during the impact that lead to the fracture.
32
VIEW
ML00183 / Dec.2022
Ductile Behavior of an Aluminum Wheel
M - Aluminum Silicon MagnesiumP - CastingAp - AutomotiveCd - Ductile Behavior
Cm - Micrography by SEMDf - Brittle Cracks
Ductile Behavior of an Aluminum Wheel
2
VIEW
ML00183 / Dec.2022
Ductile Behavior of an Aluminum Wheel
M - Aluminum Silicon MagnesiumP - CastingAp - AutomotiveCd - Ductile Behavior
Cm - Testpiece aspectDf - Fracture
Ductile Behavior of an Aluminum Wheel
2
VIEW
ML00183 / Dec.2022
Ductile Behavior of an Aluminum Wheel
M - Aluminum Silicon MagnesiumP - CastingAp - AutomotiveCd - Ductile Behavior
Cm - Testpiece aspectDf - Fracture
Dendritic branching structure of the aluminum matrix, with fine interdendritic features visible against a darker surrounding phase.
2
VIEW
ML00183 / Dec.2022
Ductile Behavior of an Aluminum Wheel
M - Aluminum Silicon MagnesiumP - CastingAp - AutomotiveCd - Ductile Behavior
Cm - Keller Etched Micrography by OMDf - Crack