(中南大學(xué) 材料科學(xué)與工程學(xué)院，長(zhǎng)沙 410083)
摘 要: 通過(guò)顯微硬度測(cè)試、常規(guī)拉伸性能測(cè)試、DSC分析和透射電鏡觀察，研究少量Zn元素及時(shí)效工藝對(duì)2056鋁合金微觀組織與力學(xué)性能的影響。結(jié)果表明：在T6、T8和T3時(shí)效狀態(tài)下，2056合金的抗拉強(qiáng)度(σb)和屈服強(qiáng)度(σ0.2)均比不含Zn合金的高，而伸長(zhǎng)率(δ)相差不大，這是因?yàn)閆n的添加形成富Zn 團(tuán)簇，促進(jìn)GPB區(qū)的形成，進(jìn)一步促進(jìn)S′相的析出，提高合金強(qiáng)度。2056合金在T6、T8峰時(shí)效態(tài)和T3態(tài)下的σb和σ0.2由大到小順序?yàn)門(mén)8，T3和T6，時(shí)效前的預(yù)變形形成大量位錯(cuò)，由于位錯(cuò)和溶質(zhì)原子強(qiáng)烈的交互作用，形成大量的位錯(cuò)塞積和纏結(jié)，增加了T3態(tài)合金的強(qiáng)度；在T8態(tài)下，大量的位錯(cuò)成為S′相的形核點(diǎn)，使合金形成細(xì)小、密集和均勻彌散的S′相，其強(qiáng)度較T6和T3態(tài)的得到較大提高。
關(guān)鍵字: 2056鋁合金；Zn；時(shí)效處理；力學(xué)性能；微觀組織
（School of Materials Science and Engineering, Central South University, Changsha 410083, China）
Abstract:The effects of Zn additions and aging process on the microstructure and mechanical properties of 2056 aluminum alloy were investigated by micro-hardness test, tensile test, differential scanning calorimetry (DSC) and transmission electron microscopy (TEM). The results show that the tensile strength (σb) and yield strength (σ0.2) of 2056 aluminum alloy are higher than those of the alloy without Zn while the elongation is almost the same in T6, T8 and T3 temper. This is because with the addition of Zn, Zn-rich clusters form, which accelerates the precipitation of GPB zone and the precipitation of S′ phase further, thus improving the strength of the alloy. The order of σb and σ0.2 of 2056 aluminum alloy in T3, peak-aged T6 and T8 temper from large to small is T8, T3 and T6. The predeformation before aging makes plenty of dislocations form. Due to the strong interaction between the solute atoms and dislocations, there exists large quantity of dislocation pile-up while dislocations become tangled up, which improve the strength in T3 temper. In T8 temper, the dislocations become the precipitation sites of S′ phase, making fine, dense and uniform S′ phase in the matrix. The strength of the alloy in T8 temper improves a lot compared with that of T6 and T3 temper.
Key words: 2056 aluminum alloy; Zn; aging treatment; mechanical properties; microstructure
