The aim of the present study was to carry out a microstructural and mechanical characterization of the A354 (Al-Si-Cu-Mg) cast aluminum alloy. The effect of microstructure on the tensile behaviour was evaluated by testing samples with different Secondary Dendrite Arm Spacing, (SDAS) values (20-25 μm and 50-70 μm for fine and coarse microstructure, respectively), which were produced through controlled casting conditions. The tensile behaviour of the alloy was evaluated both at room and elevated temperature (200 °C), in the heat treated and overaged (exposure at 210 °C for 41 h, after solution heat treatment) conditions. Optical, scanning electron microscopy (SEM) and scanning transmission electron microscopy (STEM) were used for microstructural investigations. Experimental data confirmed the significant role of microstructural coarseness on the tensile behaviour of A354 alloy. Ultimate tensile strength and elongation to failure strongly increased with the decrease of SDAS. Moreover, solidification rate influenced other microstructural features, such as the eutectic silicon morphology as well as the size of the intermetallic phases, which in turn also influenced elongation to failure. Coarsening of the strengthening precipitates was induced by overaging, as observed by STEM analyses, thus leading to a strong reduction of the tensile strength of the alloy, regardless of SDAS. Tensile properties of the alloy sensibly decrease at elevated temperature (200 °C) in all the investigated heat treatment conditions.
Ceschini, L., Morri, A., Toschi, S., Johansson, S., Seifeddine, S. (2015). Microstructural and mechanical properties characterization of heat treated and overaged cast A354 alloy with various SDAS at room and elevated temperature. MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, 648, 340-349 [10.1016/j.msea.2015.09.072].
Microstructural and mechanical properties characterization of heat treated and overaged cast A354 alloy with various SDAS at room and elevated temperature
CESCHINI, LORELLA;MORRI, ALESSANDRO;TOSCHI, STEFANIA;
2015
Abstract
The aim of the present study was to carry out a microstructural and mechanical characterization of the A354 (Al-Si-Cu-Mg) cast aluminum alloy. The effect of microstructure on the tensile behaviour was evaluated by testing samples with different Secondary Dendrite Arm Spacing, (SDAS) values (20-25 μm and 50-70 μm for fine and coarse microstructure, respectively), which were produced through controlled casting conditions. The tensile behaviour of the alloy was evaluated both at room and elevated temperature (200 °C), in the heat treated and overaged (exposure at 210 °C for 41 h, after solution heat treatment) conditions. Optical, scanning electron microscopy (SEM) and scanning transmission electron microscopy (STEM) were used for microstructural investigations. Experimental data confirmed the significant role of microstructural coarseness on the tensile behaviour of A354 alloy. Ultimate tensile strength and elongation to failure strongly increased with the decrease of SDAS. Moreover, solidification rate influenced other microstructural features, such as the eutectic silicon morphology as well as the size of the intermetallic phases, which in turn also influenced elongation to failure. Coarsening of the strengthening precipitates was induced by overaging, as observed by STEM analyses, thus leading to a strong reduction of the tensile strength of the alloy, regardless of SDAS. Tensile properties of the alloy sensibly decrease at elevated temperature (200 °C) in all the investigated heat treatment conditions.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
