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基于液态压铸技术,研究了压射速度对Al-20%Si合金显微组织与性能的影响,同时利用扫描电子显微镜(SEM)对其拉伸断口形貌进行分析。结果表明:随着压射速度的增大,试样的抗拉强度、伸长率和冲击韧度先增大而后减小,硬度总的趋势是降低的,但硬度值变化不大。合金的断裂方式为解理断裂。在实验条件下,增压压力16MPa、模具温度150℃、浇注温度720℃、压射速度2.5m/s时,压铸Al-20%Si合金的力学性能较优,其力学性能可以达到:σb=280MPa、δ5=4.83%、Ak=25.56 J/cm2、硬度=80.6HBS。
Based on the liquid die-casting technology, the effect of injection velocity on the microstructure and properties of Al-20% Si alloy was studied. The tensile fracture morphology was analyzed by scanning electron microscope (SEM). The results show that with the increase of injection rate, the tensile strength, elongation and impact toughness of the sample first increase and then decrease, the general trend of hardness decreases, but the hardness value does not change much. Alloy fracture mode cleavage fracture. Under the experimental conditions, the mechanical properties of the die-cast Al-20% Si alloy are better when the supercharging pressure is 16MPa, the die temperature is 150 ℃, the pouring temperature is 720 ℃ and the shot velocity is 2.5m / s. 280 MPa, δ5 = 4.83%, Ak = 25.56 J / cm2, hardness = 80.6 HBS.