## 1 Introduction  
Due to problems with the regulation of environments and fuel efficiency, it is necessarily required to use lightweight materials in various industries, such as automotive, marine, and aerospace fields. Under such circumstances, aluminum alloy has been given attention by many industries owing to the significant advantages of lighter weight, excellent corrosion resistance, and high-strength stiffness to weight ratio [1]. In particular, AlSi10 MnMg (Silafont-36, AA365) alloy is the first successful aluminum-silicon alloy of low iron content and has many benefits, such as good castability, excellent wear, and corrosion resistance, and high elongation [2]. Moreover, this alloy has been primarily produced by the high-pressure die-casting (HPDC) process, which has contributed to high productivity and capability to produce complicated components [3, 4]. With such advantages, the HPDC AA365 alloy has been employed extensively as automotive components, notably powertrain systems in automobiles, such as a cylinder head, engine block, and engine room parts [2]. However, the components adjacent to the engine are exposed to high-temperature and corrosive environments. So, these parts should be required for excellent corrosive resistance and high-temperature mechanical property. In addition, the HPDC process can give rise to many defects, such as micro-voids and trapped gas, and the defects can provoke the inferior performance of the alloy parts by propagating cracks [2, 5, 6, 7]. In terms of the microstructure of Al-Si alloy, \(\alpha\)-Al phase, hard Si phase, and brittle intermetallic phases are usually found. In this, intermetallic phases are laid mainly as \(\beta\)-Al\({}_{5}\)SiFe, \(\alpha\)-Al\({}_{15}\)(Mn,Fe)\({}_{3}\)Si\({}_{2}\), Mg\({}_{2}\)Si, and \(\pi\)-Al\({}_{8}\)Mg\({}_{3}\)FeSi\({}_{6}\)[8, 9, 10]. In the corrosive environment, the Si particle and intermetallic phases react as local cathodes with respect to the \(\alpha\)-Al phase, generating localized corrosion through the eutectic areas [7]. In other words, they can lead to the formation of micro-galvanic couples, degrading the performance of the Al alloy. However, the effect of the Si particles would be insignificant because of the low current density, as a result of the high polarization of the particles comparatively [7]. Instead, the intermetallic compounds may lead to intense galvanic couples with the \(\alpha\)-Al matrix, showing severe pitting corrosion on the parts. Previous research has investigated the various characteristics of AlSi10 MnMg alloys. In terms of the microstructure, casting defects, heat treatment, mechanical properties, and corrosion resistance of the alloy have been examined [11; 12; 13; 14]. Furthermore, it was found that the characteristics have been varied, depending on the cooling rates of AlSi10 MnMg alloy after T4 (solidification + solid solution treatment) and T6 heat treatments (solidification + solid solution treatment + artificial aging) [9]. Especially, the superior creep resistance of the alloy has been proved under the various high-temperature and applied stresses, of which this ability was attributed to the threshold stress which stemmed from the interaction of dislocations and intermetallic compounds [2]. However, few studies have been conducted about the corrosion properties of an AlSi10 MnMg alloy affected by applied stress under high temperature. The purpose of this research was to investigate the corrosion behavior of crept AlSi10 MnMg alloy (AA365) from the point of microstructural view, in order to contribute to improving the reliability and long-term structural performance of this application in the automotive industry. To examine this characteristic of the alloys, this study revealed the correlation between the corrosion resistance and the microstructures, notably intermetallic compounds and micro-voids, of crept AA365 alloys affected by various temperatures and stresses.