Effect of Cr and W on the Crystallization Process, the Microstructure and Properties of Hypoeutectic Silumin to Pressure Die Casting

Abstract

This article presents the results of studies in the hypoeutectic silumin destined for pressure die casting with the simultaneous addition of chromium and tungsten. The study involved the derivative and thermal analysis of the crystallization process, metallographic analysis and mechanical properties testing. Silumin 226 grade was destined for studies. It is a typical silumin to pressure die casting. AlCr15 and AlW8 preliminary alloys were added to silumin. Its quantity allowed to obtain 0.1, 0.2, 0.3 and 0.4% of Cr and W in the tested alloy. Studies of the crystallization process as well as the microstructure of the silumin poured into DTA sampler allowed to state the presence of additional phase containing 0.2% or more Cr and W. It has not occurred in silumin without the addition of above mentioned elements. It is probably the intermetallic phase containing Cr and W. DTA studies have shown this phase crystallizes at a higher temperature range than α (Al) solid solution. In the microstructure of each pressure die casting containing Cr and W the new phases formed. Mechanical properties tests have shown Cr and W additives in silumin in an appropriate amount may increase its tensile strength Rm (about 11%), the yield strength Rp0.2 (about 21%) and to a small extent elongation A.

Data Mining Methods for Prediction of Multi-Component Al-Si Alloy Properties Based on Cooling Curves

“…The preliminary tests carried out confirmed the possibility of obtaining higher-strength properties of Al-Si alloys predestined to pressure die casting as a result of the discussed high-melting element additives (Ref [18][19][20][21]. The second part of this paper describes the experimental procedure of material studies.…”

Archives of Metallurgy and Materials

“…Aluminum alloy castings, depending on the production technology and heat treatment, have different mechanical properties, which in some applications are too low. Improvement of mechanical properties of castings of aluminum and silicon alloys is obtained as a result of appropriate treatments on a liquid alloy such as: modification of morphology of silicon eutectic particles [3], introduction of alloy additives [4,5], and in the case of manufacturing of castings by: application of intensive cooling [6,7] or heat treatment [8] castings.…”

Archives of Foundry Engineering

“…The foundry alloys of Al-Si system (silumins) are characterized by the high yielding, average plasticity, good strength and hardness [1]. The principal specifications of the manufactured products are determined by the method of casting and the presence of thermal treatment.…”