微合金化对Al-Cu-Li-Zr合金拉伸性能和微观组织的影响

Influences of microalloying on tensile properties and microstructure of alloy Al-Cu-Li-Zr

通过拉伸测试和TEM观察研究了Mg、Zn、Mn微合金化对Al-Cu-Li-Zr合金力学性能和微观组织的影响。结果表明:与基础合金相比,Mg、Zn、Mn微合金化的Al-3.1Cu-2.1Li-0.1Zr合金T6时效时的强度较高,峰值强度提高约40 MPa,且在低温T8时效时的时效响应速率明显加快,同时具有较低的各向异性。Al-Cu-Li-Zr合金的析出相为大量δ'相、T1相和少量θ'相。T6时效时,微合金元素的添加显著增大δ'相、T1相和θ'相的析出密度,且出现少量S'相。低温T8时效时,微合金元素的添加有效促进δ'相和T1相细小弥散地析出。

Influences of microalloying Mg, Zn, Mn on tensile properties and microstructure of alloy Al-Cu-Li-Zr were investigated by ten- sile test and TEM observation. Results show that compared with base alloy, the microalloying Mg, Zn, Mn alloy Al-3.1Cu-2. 1Li-0. 1Zr has higher strength after T6 aging, whose peak is improved by about 40 MPa. And the aging response of microalloying alloy is faster under T8 condition. Meanwhile, the anisotropy index of the strength of microalloyed alloy is lower. The main precipitated phases of alloy A1-Cu- Li-Zr increase for δ＇, T1 and decrease for θ＇. During T6 aging, the precipitated densities of δ＇, T1 and θ＇ are obviously improved by adding micro alloy, meanwhile less S＇ phase is observed. During T8 aging, more disperse phases of δ＇, T1 are effectively precipitated by adding microalloying elements.