Search Results (3)

The microstructure is an important factor determining the mechanical properties of A356 alloy. In this experiment, the refiner Al-5Ti-0.6C-1.0Ce master alloys under different preparation temperatures were prepared, and the A356 alloy was refined. The effects of preparation temperature on the number and morphological distribution of each phase in Al-Ti-C-Ce master alloy and the effects of Al-Ti-C-Ce master alloy at different preparation temperatures on the microstructure and mechanical properties of A356 alloy were explored successively. Results showed that, as preparation temperature increased from 850 to 1150 °C, TiAl₃ changed from large blocks to long strips and a needle-like phase, and Ti₂Al₂₀Ce changed from a bright white block to a broken small block phase. Al-5Ti-0.6C-1.0Ce prepared at 1050 °C can significantly refine the α-Al of A356 alloy and modify eutectic Si. The α-Al grain size was refined from about 1540 to 179.7 μm, and the eutectic Si length was refined from about 22.3 to 17.8 μm with the transition from a coarse needle-like to a short rod-like structure. The ultimate tensile strength and elongation of A356 alloy changed non-monotonically, and the peak values were 282.216 MPa and 3.9% with the Al-Ti-C-Ce preparation temperature of 1050 °C and 950 °C, respectively. Full article

The effects of CeO₂ size on the microstructure and synthesis mechanism of Al-Ti-C alloy were investigated using a quenching experiment method. A scanning calorimetry experiment was used to investigate the synthesis mechanism of TiC, the aluminum melt in situ reaction was carried out to synthesize master alloys and its refining performance was estimated. The results show that the Al-Ti-C-Ce system is mainly composed of α-Al, Al₃Ti, TiC and Ti₂Al₂₀Ce. The addition of CeO₂ obviously speeds up the progress of the reaction, reduces the size of Al₃Ti and TiC and lowers the formation temperature of second-phase particles. When the size of CeO₂ is 2–4 μm, the promotion effect on the system is most obvious. The smaller the size of CeO₂, the smaller the size of Al₃Ti and TiC and the lower the formation temperature. Al-Ti-C-Ce master alloy has a significant refinement effect on commercial pure aluminum. When the CeO₂ size is 2–4 μm, the grain size of commercial pure aluminum is refined to 227 μm by Al-Ti-C-Ce master alloy. Full article

Al-5Ti-0.62C-0.2Ce master alloy was synthesized by a method of thermal explosion reaction in pure molten aluminum and used to modify commercial pure Al and hypoeutectic Al-8Si alloy. The microstructure and tensile properties of commercial pure Al and hypoeutectic Al-8Si alloy with different additions of Al-5Ti-0.62C-0.2Ce master alloy were investigated. The results show that the Al-5Ti-0.62C-0.2Ce alloy was composed of α-Al, granular TiC, lump-like TiAl3 and block-like Ti2Al20Ce. Al-5Ti-0.62C-0.2Ce master alloy (0.3 wt %, 5 min) can significantly refine macro grains of commercial pure Al into tiny equiaxed grains. The Al-5Ti-0.62C-0.2Ce master alloy (0.3 wt %, 30 min) still has a good refinement effect. The tensile strength and elongation of commercial pure Al modified by the Al-5Ti-0.62C-0.2Ce master alloy (0.3 wt %, 5 min) increased by roughly 19.26% and 61.83%, respectively. Al-5Ti-0.62C-0.2Ce master alloy (1.5 wt %, 10 min) can significantly refine both α-Al grains and eutectic Si of hypoeutectic Al-8Si alloy. The dendritic α-Al grains were significantly refined to tiny equiaxed grains. The morphology of the eutectic Si crystals was significantly refined from coarse needle-shape or lath-shape to short rod-like or grain-like eutectic Si. The tensile strength and elongation of hypoeutectic Al-8Si alloy modified by the Al-5Ti-0.62C-0.2Ce master alloy (1.5 wt %, 10 min) increased by roughly 20.53% and 50%, respectively. The change in mechanical properties corresponds to evolution of the microstructure. Full article