稀土Ce对ZA27合金组织和力学性能的影响

Influence of rare-earth Ce on microstructure and mechanical properties of ZA27 alloy

在ZA27合金中加入稀土元素Ce,并采用挤压铸造的加工方法,寻求细化组织和提高力学性能的途径.稀土Ce使ZA27合金的晶粒细化,β相和ε相分布更均匀,并且在晶界处生成了不规则的化合物,该化合物包含Zn、Al、Cu、Ce、Mg等元素.随着含Ce量的增加,化合物的数量增多,有少量偏聚成大块.在挤压力作用下,晶界处ε相要少些.添加稀土Ce后,挤压铸造ZA27合金的抗拉强度、伸长率、硬度均有所提高.结果表明,含Ce量为0.15%时挤压铸造ZA27合金组织和力学性能最好.

Through adding rare-earth Ce to ZA27 alloy and using squeeze casting technology, the methods to refine microstructure and enhance mechanical properties were investigated. Due to the addition of rare-earth Ce to ZA27 alloy, the grains get refined, and the distribution of β and ε phases becomes more homogeneous. At the grain boundaries, a series of irregular compounds form, which contain such elements as Zn, Al, Cu, Ce and Mg. With the increase of Ce, the amount of compounds increases, and some of them gather into large compounds. Under squeeze pressure, the amount of ε phases at grain boundaries is less. With the addition of rare-earth Ce, the tensile strength, elongation and hardness of the squeeze casting ZA27 alloy get enhanced. The results show that the squeeze casting ZA27 alloy with the Ce content of 0.15 % has the optimal microstructure and mechanical properties.