Microstructure and Corrosion Characterization of Squeeze Cast AM50 Magnesium Alloys

Abstract

Squeeze casting of magnesium alloys potentially can be used in lightweight chassis components such as control arms and knuckles. This study documents the microstructural analysis and corrosion behavior of AM50 alloys squeeze cast at different pressures between 40 and 120 MPa and compares them with high-pressure die cast (HPDC) AM50 alloy castings and an AM50 squeeze cast prototype control arm. Although the corrosion rates of the squeeze cast samples are slightly higher than those observed for the HPDC AM50 alloy, the former does produce virtually porosity-free castings that are required for structural applications like control arms and wheels. This outcome is extremely encouraging as it provides an opportunity for additional alloy and process development by squeeze casting that has remained relatively unexplored for magnesium alloys compared with aluminum. Among the microstructural parameters analyzed, it seems that the b-phase interfacial area, indicating a greater degree of b network, leads to a lower corrosion rate. Weight loss was the better method for determining corrosion behavior in these alloys that contain a large fraction of second phase, which can cause perturbations to an overall uniform surface corrosion behavior.

Solidification Microstructure and Mechanical Properties of Cast Magnesium-Aluminum-Tin Alloys

“…No stable ternary phase was discovered, and no ternary solubility of the binary intermetallic phases was found in this calculation, which is consistent with a previous study. [10] Two binary phases, Mg 2 Sn and Mg 17 Al 12 , are important to this alloy system; the Mg 2 Sn phase is reported to provide significant strengthening, [3] whereas the Mg 17 Al 12 phase improves strength, [12] corrosion, and castability, [13] but reduces ductility and creep resistance. [2] In designing new Mg-Al-Sn alloys for automotive structural applications, mechanical properties and corrosion resistance are primary considerations.…”

On effect of squeezing pressure on microstructural characteristics, heat treatment response and electrical conductivity of an Al-Si-Mg-Ni-Cu alloy

“…Owing to these unique and desirable properties, Al-Si alloys are extensively used in the industry. [11][12][13][14] These alloys are normally solution heat treated, quenched and subsequently aged to achieve a good combination of tensile strength and ductility.…”

Influence of periodic pressure on dendritic morphology and sidebranching

“…Based on the formulation to calculate sidebranching frequency, i.e., Eqs. (8) and 9, the SDAS is associated with sidebranching frequency, no matter how high the frequency of pressure is, as seen from Figs. 4 and 7.…”