Microstructural properties of sintered Al–Cu–Mg–Sn alloys Çig˘dem O ¨ zay 1 • Elif Beyza Gencer 2 • Azim Go¨ kçe 3 Received: 12 October 2017 / Accepted: 4 March 2018 Ó Akade´miai Kiado´, Budapest, Hungary 2018 Abstract A non-commercial Al4Cu0.5Mg alloy has been used for investigating the effects of the elemental Sn additions. Uniaxial die compaction response of the alloys in terms of green density was examined, and the results showed that Sn addition has no effect when compacting conducted under high pressures. In total, 93–95% green density was achieved with an applied pressure of 400 MPa. Thermal events occurring during the sintering of the emerging alloys were studied by using differential scanning calorimetry (DSC). First thermal event on the DSC analysis of the Al4Cu0.5Mg1Sn alloy is the melting of elemental Sn, whereas for Al4Cu0.5Mg alloy, it is the formation of Al–Mg liquid nearly at 450 °C. Also it is clearly seen on the DSC analysis that Sn addition led to an increase in the formation enthalpy of Al–Mg liquid phase. High Sn content and high sintering temperature (620 °C), therefore high liquid-phase content, caused decrease on the mechanical properties due to thick intergranular phases and grain coarsening. Highest transverse rupture strength and hardness values were obtained from Al4Cu0.5Mg0.1Sn alloy sintered at 600 °C and measured as 390 MPa and 73 HB, respectively. Keywords Aluminium alloys Á Powder metallurgy Á Sintering Á Thermal analysis Introduction Powder metallurgy (PM) is a relatively new method com- pared to other manufacturing methods such as casting and machining, and it offers fast and economical production. PM process can easily be automated, and this property makes it a preferred method for producing automobile parts [1]. Generally, motor and transmission parts are produced by using PM- and Fe-based powders [2]. Using light alloys such as Al and Mg instead of steel is very common for decreasing the vehicle’s weight, CO 2 emissions and fuel consumption [3–5]. Aluminum PM alloys attract the attention of automotive producers, but there are limited numbers of commercial aluminum PM alloys. The prop- erties of these alloys were extensively investigated in the literature [6, 7]. Most of the aluminum PM alloys are produced through adding alloying elements to the Al–Cu binary system (2XXX series). The major disadvantage of Al alloys against steel is their low strength. Researchers focused on producing high strength Al alloys by using various methods, and one of these methods is to develop new non-commercial aluminum PM alloys. It was previ- ously reported that even minor addition of alloying element can improve the mechanical properties of the aluminum PM alloys significantly [8]. Alloying elements such as Mg, Fe, Pb, In, Zn, Ni, Si and Sn are used for strengthening the aluminum PM alloys [9–13]. Gordo et al. [14] stated that a second liquid phase with lower surface energy improves the wettability of the solid powder particles. Elements with low melting point and low surface energy (such as Sn) are to be considered as appropriate alloying elements for enhanced wetting of particles by liquid phase. Kondoh et al. [15] claimed that the addition of Sn into aluminum PM alloys enhances the mechanical properties by preventing the AlN formation during sintering. Momeni et al. [16] studied the effects of Sn addition on the prealloyed 2024 powder and observed that higher Sn content causes better wettability. Sercombe and Schaffer [9] reported that vacancy binding energy and diffusivity of & Azim Go¨kc¸e azimg@sakarya.edu.tr 1 Armetal Surface Treatment Ltd., Bolu Organized Industrial Zone, Bolu, Turkey 2 Adalı Machinery, Adapazarı, Sakarya, Turkey 3 Metallurgical and Materials Engineering Department, Technology Faculty, Sakarya University, Sakarya, Turkey 123 Journal of Thermal Analysis and Calorimetry https://doi.org/10.1007/s10973-018-7171-5