微量元素Cr、Mg对Zn-Cu-Ti合金力学和蠕变性能的影响

采用熔铸、挤压的方法制备了添加Cr、Mg等微量元素的Zn-Cu-Ti系合金, 通过蠕变试验测定了合金的拉伸蠕变性能, 借助SEM、EDS等手段对合金蠕变前后显微组织进行了观察和分析。结果表明: 添加微量元素可降低Zn-Cu-Ti合金常温蠕变速率, 提高合金蠕变抗力。其中添加了Cr元素的Zn-Cu-Ti合金抗拉强度、蠕变性能都有一定的提高；添加了微量元素Mg的Zn-Cu-Ti合金抗拉强度有一定提高, 其蠕变抗力有大幅度提高。Zn-Cu-Ti系合金的常温蠕变机制为位错在晶内的滑移机制, 固溶强化和晶界处的第二相颗粒能提高合金的抗蠕变性能。

Effect of Trace Elements Cr and Mg on Mechanics and Creep Properties of Zn-Cu-Ti Alloys

Zn-Cu-Ti alloys doped with trace elements Cr and Mg were prepared by using the methods of smelting and extrusion. The tensile creep properties of the alloys were measured through the creep test. The microstructures of the alloys before and after creep were observed and analyzed by SEM and EDS. The results showed that adding trace elements could reduce the normal-temperature creep rate of Zn-Cu-Ti alloys and increase the creep resistance of the alloy. Both of the tensile strength and creep properties of Cr-doped Zn-Cu-Ti alloy were improved to a certain extent. The tensile strength of Mg-added Zn-Cu-Ti alloy was improved while the creep resistance was greatly improved. The mechanism of normal-temperature creep of Zn-Cu-Ti alloys is the slippage of dislocation in the crystals. Solid solution strengthening and the second phase particles at the grain boundaries can improve the creep resistance of the alloys.