Oxide Scale Behavior and Surface Protection of Al–Mg Alloys Containing a Trace of Ca

Does Expanding or Contracting MgO Lattice Really Help with Corrosion Resistance of Mg Surface: Insights from Molecular Dynamics Simulations

“…The PB ratio is often used to discuss the effectiveness of a protective layer. 1 , 5 , 8 It is the ratio of the volume occupied by a metal atom in the oxide to the volume occupied by the same metal atom in the substrate. 5 When the MgO/Mg PB ratio is 0.81, the corresponding L ( a / a 0 ) is 1.00.…”

“…MgO/Mg has a PB ratio ( V MO / V M ) at 0.81 which is smaller than 1, and it is believed that the poor corrosion resistance of Mg alloys results from the incomplete coverage of MgO. 2 − 8 Furthermore, MgO itself is a hydrophilic material, and water droplets on the MgO surface can act as a medium to accelerate corrosion in a humid environment. If the solid material has hydrophobic properties, the surface of the material will remain “clean” and corrosion may be retarded to a certain extent.…”

“…According to the Pilling–Bedworth (PB) theory, metallic materials which form bigger oxide crystal lattices than the substrate will lead to excellent corrosion protections, while those forming smaller oxidation volumes at the surface will result in poor protections. MgO/Mg has a PB ratio ( V MO / V M ) at 0.81 which is smaller than 1, and it is believed that the poor corrosion resistance of Mg alloys results from the incomplete coverage of MgO. − Furthermore, MgO itself is a hydrophilic material, and water droplets on the MgO surface can act as a medium to accelerate corrosion in a humid environment. If the solid material has hydrophobic properties, the surface of the material will remain “clean” and corrosion may be retarded to a certain extent.…”

Stretch Forming Behavior and Constitutive Equation of a Modified 5083 Alloy with High Mg Content at Elevated Temperatures

“…Table 1 showed the chemical compositions of the 5083M alloy with the commercial 5083 alloy. The slab of 5083M alloy was cast using high-purity aluminum ingot, Mg master alloy including Al 2 Ca, which was used for inhibiting Mg oxidation for the quality of molten metal, and Al-Ti mother alloy with induction furnace in the laboratory [18,19]. The slab was homogenized at 430 • C for 24 h to eliminate segregation.…”

Hot Compression Behavior of New Al-6Mg and Al-8Mg Alloy with Improved Hot Workability Fabricated by Direct Chill Casting Method

“…Furthermore, in general, Mg solutes in Al-Mg alloys are distributed not uniformly, so that the strain anisotropy occurs [8,9]. In order to overcome these difficulties, several Al-Mg with high Mg hot working technics have been investigated in past years [10][11][12]. Nevertheless, the optimum hot working conditions of Al-6Mg and Al-8Mg have not been investigated and discussed sufficiently.…”