FABRICATION OF CAST ALUMINIUM-SILICON (Al-Si) AND ALUMINIUM-MAGNESIUM (Al-Mg) ALLOYS AND THEIR PROPERTIES

Abstract

In the present investigation, three distinct aluminium-silicon (Al-Si) containing 7 wt.%, 12 wt.%, 14 wt.% of silicon and two different aluminium-magnesium (Al-Mg) alloys containing 2.5 wt.%, 4.5 wt.% of magnesium were prepared by casting route method. The prepared Al-Si and Al-Mg alloys have homogeneous distribution of the second rich phase throughout the cast. The microstructural analysis was done by using both optical and scanning electron microscope. Hardness values were measured with a Vickers hardness tester and tensile properties were determined by using Instron universal testing machine. Further, the wear properties were studied by using a ball-on-plate wear tester. The obtaining results highlight the hardness, tensile properties and wear resistance are increases with increasing percentage of second rich phase in aluminium. The worn surfaces of these alloys revealed that the surfaces have cracks, grooves, scoring marks and debris.

Analysis of the Causes of Distortion Castings After Heat Treatment

“…Quality of cylinder heads firstly depends on adherence to a technological discipline during production and secondly on influences during heat treatment [4]. Below are examples of some specific influences that affect the quality of castings:  impact of quality cores -cores quality affects the functionality of the casting, which is checked at every casting with using tightness tests,  influence of the chemical composition of the poured melted alloy -lower quality of the alloy will be seen through the presence of non-metallic inclusions, heterogeneous microstructure and the casting's characteristics,  influence of cleanliness of the cast-iron mould -presence of dirts on the surface of the metal form is manifested by surface defaults in the casting,  influence of parameters of heat treatment -several risk factors exist, which can influence mainly the shape and dimensions of a casting, which would threaten the quality of functional areas of the cylinder heads and dimensions of the castings.…”

“…A disadvantage of this method is the application of structural solutions requires a number of preliminary tasks and can only be used during higher production [1,2]. Recently, Al-Si alloys find applications in such tribological components such as clutches, cylinder liners and pistons in the automotive industry [4].Companies that make products for the automotive industry adhere to the STN P ISO/TS 16 949:2009 norm -QMS, Individual Requirement for using norm ISO 9001:2008 in an organization production of automobiles and replacement parts, which specifies strict conditions for quality production. The goal of the technical specification is to prepare a DOI QMS appropriate for continuous improvement with emphasis on prevention of defects and to limit deviations and losses within the supply chain [5].…”