分段慢压射速度对AZ91D镁合金真空压铸件组织的影响（英文）

• 作 者: 王青亮 熊守美
• 机 构: 清华大学材料学院,清华大学汽车安全与节能国家重点实验室,
• 出 处: Transactions of Nonferrous Metals Society of China
• 发表日期: 2015年02期
• 关键词: 压射速度 AZ91D镁合金 压铸件 真空压铸 充型 真空压力 真空传感器 金属液 压室 filling

在AZ91D镁合金真空压铸过程中使用2种分段慢压射速度(两段和三段)。在充型之前型腔内真空压力变化情况通过真空传感器进行监测。压铸件组织通过光学显微镜和图像分析软件进行分析。结果表明,采用三段慢压射速度时充型时刻型腔真空压力明显降低,导致所得压铸件中气孔含量很低。通过恰当选用分段慢压射速度,在充型之前金属液在压室中的停留时间可缩短,在慢压射过程后期阶段金属液在压室中的流动也将受到抑制,这些因素可导致所得压铸件中压室预结晶组织含量较低。

Two types of slow injection velocities (two and three stages) were used in the vacuum die casting of AZ91D magnesium alloy. Vacuum pressure changes in the cavity before filling are monitored by vacuum sensors. Die-castings were analyzed by light microscopy and image analysis software. The results show that the vacuum pressure of the cavity decreases obviously when the three-stage slow injection velocity is used, resulting in low porosity in the resulting die-castings. By properly selecting the slow injection velocity of the section, the residence time of the molten metal in the pressure chamber before filling can be shortened and the flow of the molten metal in the pressure chamber at a later stage of the slow pressure injection can be suppressed, which can lead to The resulting die-casting pressure chamber pre-crystallized tissue content is low.