挤压复合铸造7075/6061双金属铸锭的界面组织与性能

采用挤压复合铸造工艺制备出具有“半固态组织/枝晶组织”分布特征的7075/6061包覆型双金属复合铸锭,并对复合铸锭界面处的组织及硬度进行了分析。结果表明,界面结合良好,为冶金结合,无杂质和氧化皮存在。界面处组织过渡平缓,7075铝合金固相颗粒呈一定规律性分布;除Zn元素浓度呈明显梯度变化外,其它合金元素分布较均匀。界面大部分由较细小等轴晶组成,且有大量合金元素沉积在晶界处,致使界面处硬度高于两侧金属,硬度最高达63.3 HRB。

Interface microstructure and properties of 7075/6061 bimetallic ingot prepared by squeeze composite casting

A 7075/6061 clad bimetal composite ingot with “semi-solid structure/dendrite” distribution characteristics was prepared by squeeze composite casting technology, and the microstructure and hardness at the interface of the composite ingot were analyzed. The results show that the interface bonding is good as metallurgical bonding with no impurity and oxide scale. The transition of microstructure at the interface is smooth, and the solid particles of 7075 aluminum alloy distribute regularly; the distribution of alloy elements except for Zn is uniform. Most of the interface microstructure is composed of fine equiaxed grains, with a large quantity of alloy elements depositing at the grain boundary, resulting in the hardness of the interface higher than that on both sides, with the highest hardness of 63.3 HRB.