Akademik Veri Yönetim Sistemi
INTERNATIONAL JOURNAL OF METALCASTING, cilt.19, sa.1, ss.544-558, 2025 (SCI-Expanded, Scopus)
This study investigates the effect of two-step solution treatments and aging times on the microstructure and mechanical properties of B357 Al-Si alloy, part of the most widely used cast aluminum alloy. Three sets of artificial aging heat treatments were conducted on the tensile samples prepared from B357 alloy produced by low-pressure die casting. Firstly, the conventional artificial aging heat treatment (T6) was carried out by solutionizing the tensile samples at 543 degrees C for 8.5 h, water quenching at 60 degrees C, and then artificially aging for 8.5 h at 160 degrees C. In the two-step solution treatment, the samples were solutionized at 400, 440, 480, and 520 degrees C for 4 h and then solutionized at 543 degrees C for 8.5 h and water quenched to 60 degrees C and then artificially aged for 8.5 h at 160 degrees C. Thirdly, the samples were solutionized at 480 degrees C for 4 h, solutionized at 543 degrees C for 8.5 h, water quenched to 60 degrees C, and artificially aged for 3-192 h. Despite different solutioning and aging processes, no significant differences were observed in the microstructures of the samples. Si particle coarsening was observed with increasing solution temperature (400-520 degrees C) and aging times (3-192 h). Si-containing dispersoids and dispersoid-free zones (DFZ) were observed in the primary-alpha matrix. While DFZ width increased with temperature and aging, dispersoid zones in primary-alpha dendrites significantly decreased. Differential Scanning Calorimetry (DSC) analysis shows that two-step solution treatment in B357 alloy increases beta ' precipitates for Mg2Si precipitation strengthening. The two-step solutionized and aged sample showed the best combination of strength and ductility among all aged samples. B357 alloy exhibited the highest yield and tensile strength (309.7, 366.1 MPa) with 6% elongation for two-step solutionizing and 48 h aging. All aged B357 alloys showed ductile fracture as the primary fracture mode. However, brittle fractured Si particles were observed on the fracture surfaces.