Microstructure And Properties Of ?Al₂O₃+Al₃Zr?_p/ZL104 Composites Prepared By Electromagnetic Stirring

Metal matrix composites are one of the most promising advanced materials in the21st century due to their high specific strength,specific stiffness and elastic modulus,low density,high temperature performance,wear resistance and fatigue resistance.The in-situ synthesis method is used to prepare a particle-reinforced metal matrix composite material by adding solid elements capable of reacting in a molten matrix alloy at a certain temperature to form fine,dispersed,stable ceramic or intermetallic compound particles.In this paper,the direct melt reaction method,an in-situ synthesis method,was used in the experimental study and ZL104+Zr?CO3?2 was used as the reaction system.The chemical reaction was fully carried out by electromagnetic stirring,and the?Al₂O₃+Al₃Zr?_p/ZL104 aluminum alloy composite was successfully prepared.In order to obtain?Al₂O₃+Al₃Zr?_p/ZL104 aluminum alloy composite with fine and uniform distribution,the electromagnetic stirring parameters were designed by single factor and orthogonal experiment.The X-ray diffractometer?XRD?,Zeiss optical microscope?OM?and scanning electron microscopy?SEM?were used as the main detection methods to analyze the phase of the composite.The distribution,morphology and size of the reactant-forming particles were quantitatively analyzed by introducing three characterization indexes of dispersibility,roundness and particle size.The results show that:at 730°C,as the electromagnetic stirring intensity increases or the electromagnetic stirring frequency decreases,the dispersibility of?Al2O3+Al3Zr?p particles was better,the?Al2O3+Al3Zr?p particles were more rounded and the particle size was smaller;however,the electromagnetic stirring time showed no obvious influence to the results when it was more than 5min.Further orthogonal analysis showed that the electromagnetic stirring intensity was the most important factor affecting the dispersion of?Al2O3+Al3Zr?p particles.The electromagnetic stirring frequency was an important factor that affects the roundness and particle size of dispersion particles.When the stirring time was 5min,the results show that the greater the stirring intensity was,the better the dispersity of the particles would be;the lower the frequency was,the better the comprehensive index of particle would be.The influence of electromagnetic stirring temperature on the distribution of?Al2O3+Al3Zr?p particles mainly reflects the influence of temperature on the morphology of primary phase??Al?.When the temperature was about 580⁶10?,the??Al?phase was fine and evenly distributed,and the dispersion of?Al₂O₃+Al₃Zr?_p particles was better.The main reason is that the enhanced phase particles were distributed at grain boundaries of?phase,the morphology of?had a great influence on the distribution of?Al₂O₃+Al₃Zr?_p particles.Further orthogonal analysis shows that the ideal parameters for preparing semi-solid aluminum matrix composites was that the stirring strength was 70%,the stirring frequency was 7 Hz,and the stirring temperature was 610?.