Effect of cooling rate and aluminum contents on the Mg-Al-Zn alloys’ structure and mechanical properties

Purpose: This work present an influence of Al concentration and cooling rate on structure and mechanical properties of magnesium alloys. Also the paper presents a methodology to predict crystallization temperatures obtained during crystallization process using an UMSA platform, based on cooling rate and chemical composition and mechanical properties and grain size based on characteristics temperatures. Design/methodology/approach: The experimental magnesium alloy used for thermal analysis and training of neural network was prepared in cooperation with the Faculty of Metallurgy and Materials Engineering of the Technical University of Ostrava and the CKD Motory plant, Hradec Kralove in the Czech Republic. The alloy was cooled with three different cooling rates in UMSA Technology Platform. The following results concern scanning electron microscopy investigations in the SE observation mode, as well as using BSE modus for better phase contrast results, also quantitative microanalysis was applied for chemical composition investigations of the phases occurred. Compression test were conducted at room temperature using a Zwick universal testing machine. Compression specimens were tested corresponding to each of three cooling rates. Rockwell F-scale hardness tests were carried out using a Zwick HR hardness testing machine. Findings: The research show that the thermal analysis carried out on UMSA Technology Platform is an efficient tool for collect and calculate thermal parameters. The formation temperatures of various thermal parameters, mechanical properties (hardness and ultimate compressive strength) and grain size are shifting with an increasing cooling rate. Practical implications: The parameters described can be applied in metal casting industry for selecting magnesium ingot preheating temperature for semi solid processing to achieve requirements properties. The presented models can be applied in computer systems of Mg-Al-Zn casting alloys, selection and designing for Mg-Al-Zn casting parts. Originality/value: The paper contributes to better understanding and recognition an influence of different solidification condition on non-equilibrium thermal parameters of magnesium alloys.