Effects of Mg content on aging behavior of Al4CuXMg PM alloy Azim Gökçe a , Fehim Fındık a,b,⇑ , Ali Osman Kurt c a Department of Metal Education, Technical Education Faculty, Sakarya University, 54187 Sakarya, Turkey b Faculty of Engineering and Natural Sciences, International University of Sarajevo, 71000 Sarajevo, Bosnia and Herzegovina c Department of Metallurgy and Materials Engineering, Engineering Faculty, Sakarya University, 54187 Sakarya, Turkey article info Article history: Received 22 July 2012 Accepted 13 October 2012 Available online 10 November 2012 Keywords: Powder metallurgy Pre-mixed powders Aluminum Magnesium Aging abstract Starting with elemental (pre-mixed) powders for producing shaped powder metallurgy alloys provides some advantages over a pre-alloyed system. The premixed powders are softer than prealloyed powders and therefore by using premixed powders it is possible to have higher compact densities and within a longer die life. In this research work, elemental aluminum powder was mixed with copper and magne- sium in various ratios. They were compacted, sintered and heat treated in order to produce light but strong Al-based powder metallurgy alloys. The main focus of this paper is on the effects of micro to macro scale addition of magnesium on the aging response of Al4Cu alloys. Four per cent Cu gives Al powder met- allurgy alloy a good control of sintering and a large space for solution treatment. Minor addition of Mg with little amount of Fe, comes from the based Al and Cu powders, enhances the hardness values of Al4Cu powder metallurgy alloys. Highest hardness value was 118 HB obtained from 24 h aged Al4Cu2Mg alloy. Ó 2012 Elsevier Ltd. All rights reserved. 1. Introduction An increasing demand of lighter but stronger alloys made aluminum a good candidate for structural applications. Advantages of aluminum, such as low density and high strength to weight ratio, high fracture toughness, good corrosion resistance and an ease of fabrication result in an extensive use in structural applica- tions especially in automotive [1,2] and aircraft industries [3–5]. Regulations about fuel efficiency and exhaust emissions pushed automotive makers to produce lighter automobiles hence usage of aluminum raised day by day. A recent work [6] showed that it is possible to produce 9.4% lighter tractors and 13.3% lighter trail- ers via using aluminum as a substitute material. Using aluminum instead of steel can result in up to 300 kg weight reduction in a medium size vehicle (1400 kg) and for every 100 kg reduction in weight can yield a cut of 0.3 to 0.6 liters per 100 km in fuel consumption, 20% lower exhaust gas emissions [7]. According to a report [8], aluminum is one of the most promising light weight materials for the next generation vehicles. Powder metallurgy (P/M) is an important processing method for producing metal parts, because of its advantages, e.g. high production efficiency, fine grain structure, homogenous micro- structure, unlimited alloy design. Especially, 2xxx and 6xxx series of aluminum alloys have been mostly investigated [9,10] for P/M applications due to their eutectic structure [11] in elevated tem- peratures [12]. Production of 2xxx series of aluminum through P/M method has been largely researched in previous works [13,14] because of their wear resistance [15], stiffness and high temperature strength [12]. Aging is a well-known strengthening mechanism for several grades of Al alloys. Previously, the effects of process conditions to the aging response of P/M (or cast) Al–Cu [16] and Al–Cu–Mg [17,18] alloys have been largely researched following the theoret- ical [19] and as well as empirical approach [20]. However, there are limited published data about the effects of minor element addi- tions to properties and aging response of Al–Cu alloys. As a minor element, Sn [21], Sn & Ag [22] and Au [23] and Mg [24] were used previously. Therefore, the main aim of this work was to investigate the influence of micro to macro scale addition of magnesium into the aging response, microstructural properties and hardness of Al4Cu powder metallurgy alloy. 2. Experimental procedure Main alloying elements of aluminum and copper were provided in powder form by Gürel Makina A.S ß. and magnesium powders by Magnezyum Metal A.S ß. The purity level of aluminum and copper powders, from supplier’s value, is 99.60% and magnesium powder is 99.95%. Particle size distribution (given in Fig. 1) of aluminum and copper were measured by Microtrac S3500 laser particle size analyzer in dry method. Due to safety reasons, particle size analysis of magnesium powders were carried out by Malvern Master Sizer 2000, which is classifies powders by settling in a liquid medium. 0261-3069/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.matdes.2012.10.045 ⇑ Corresponding author at: Department of Metal Education, Technical Education Faculty, Sakarya University, 54187 Sakarya, Turkey. Tel.: +90 264 2956487; fax: +90 264 2956424. E-mail address: findik@sakarya.edu.tr (F. Fındık). Materials and Design 46 (2013) 524–531 Contents lists available at SciVerse ScienceDirect Materials and Design journal homepage: www.elsevier.com/locate/matdes