PSI - Issue 41

Liviu Daniel Pîrvulescu et al. / Procedia Structural Integrity 41 (2022) 492–499 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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The dominant factor for a wide dispersion of fatigue life in die-cast alloys is a large dispersion of the pore size resulting from casting. The dispersion of the dimensions and the type of defect affect the fatigue life of the castings. Despair is an inherent characteristic of mechanical properties (including fatigue behavior), which is related to the reliability of structures. The fatigue process involves nucleating and the growth of cracks until the final rupture. Indicate reference by Mohd et al. (2011). Mg alloy are frequently used in mechanical engineering applications as: aerospace construction, automotive, medical devices, electronics. These alloys are used because of their advantages: lighter than aluminum, similar mechanical and thermal properties as Al alloys. But, these alloys also have a major disadvantages: it is flammable. Mg alloys have many applications in the automotive industry, Fig. 1: ➢ Transmission housings ➢ Engine blocks ➢ Steering wheel frames

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Fig.1. (a) transmission housing; (b) engine blocks; (c) steering wheel frames

Structural defects are the most difficult to identify because they are found inside the material and require special attention. These defects appear after casting in the form of porosity, cracks, inclusions in the material, Fig. 2.

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Fig.2. (a) crack; (b) voids; (c) spots

In recent years, the determination of parameters for high cycle fatigue under different loading conditions, rotating banding, axial tension - compression and multiaxial tension – torsion tests, was a priority for the automotive industry considering various magnesium alloys: ➢ AM60 Lu et al. (2008), Mohd et al. (2011), ➢ AM20 and AM50 Sonsino and Dieterich (2006), Marsavina et al. (2019), ➢ NZ series Li et al. (2015), ➢ AZ series Karr et al. (2018), Kalatehmollaei et al. (2014), Li et al. (2016), Uematsu et al. (2016). They can be identified by non-destructive testing using X-ray equipment or penetrating liquids. This paper analyzes experimentally the effect of size on the fatigue duration of Mg alloy, considering the defects resulting from casting and the quality of the surface resulting from cutting.