高温后6061-T4系铝合金板材单向循环拉伸力学性能试验研究  

Experimenal study on the mechanical properties of 6061-T4 aluminum alloy after elevated temperature under unidirectional cyclic tensile load

作　　者：赵子雁 孙国华[1] 陈慧娴 黎明 ZHAO Ziyan;SUN Guohua;CHEN Huixian;LI Ming(School of Civil Engineering,Suzhou University of Science and Technology,Suzhou 215011,China)

机构地区：[1]苏州科技大学土木工程学院,江苏苏州215011

出　　处：《地震工程与工程振动》2025年第1期166-176,共11页Earthquake Engineering and Engineering Dynamics

基　　金：国家自然科学基金项目(51578355,52378173);江苏省自然科学基金项目(BK20231343)。

摘　　要：为明晰GB 50429—2007《铝合金结构设计规范》推荐的6061-T4系铝合金板材在火灾后力学性能的退化规律,设计完成了38个6061-T4铝合金试件在室温及高温后的单向循环拉伸试验,重点评估了铝合金板材在不同冷却方式及单向循环荷载作用下的破坏特征、初始弹性模量、强度、应变退化和耗能等。研究结果表明:6061-T4铝合金板材的单向循环拉伸应力-应变曲线无明显屈服平台,显著屈服后并未呈现明显的强化特征;在加热温度为100~300℃区间时,铝合金试件表面银白色光泽变暗但不明显,表面状况不宜作为评估6061-T4铝合金试件火灾损伤程度的评价依据;温度对6061-T4铝合金初始弹性模量影响较小,冷却方式对6061-T4铝合金试件高温后力学性能影响不大。当温度低于200℃时,温度对铝合金板材强度影响不明显;当温度高于200℃时,随着温度升高,铝合金板材强度呈显著降低趋势;常温下单向循环拉伸试验过程中铝合金试件屈服应变略低于单向加载试件,由于循环受拉过程的塑性累积损伤,导致试件在单向循环荷载作用下的延性劣化;随着温度的不断升高,试件屈服会趋于更早,其变形能力呈现先变差后变好的规律;6061-T4铝合金试件累积耗能随着温度升高逐渐降低,且耗能大小与铝合金材料强度及单向循环拉伸圈数正相关。To clarify the degradation law of the mechanical property of 6061-T4 aluminum alloy after elevated temperatures as recommended by the GB 50429—2007 code for design of aluminium structures,a total of thirty-eight 6061-T4 aluminum alloy specimens were designed,and the unidirectional loading tests and cyclic tensile loading tests at room temperature and elevated temperature were performed.The effects of cooling type and loading protocol on the failure characteristics,initial elastic modulus,strength,stress degradation,and energy dissipation were evaluated.The experimental results show that the yield platform and strain hardening behavior in the unidirectional cyclic tensile stress-strain curve of 6061-T4 aluminum alloy were not observed.When the heating temperature was in the range of 100~300℃,the surface of 6061-T4 aluminum alloy specimens became slightly darker but not significantly.The surface condition of the 6061-T4 aluminum alloy can not be used as an indicator to evaluate the damage degree after fire.The temperature had a slight effect on the initial modulus of 6061-T4 aluminum alloy,and the cooling method also slightly affected the mechanical property of 6061-T4 aluminum alloy.When the temperature was below 200℃,the temperature did not have a significant effect on the strength of the aluminum alloy.When the temperature was above 200℃,the strength of 6061-T4 aluminum alloy exhibited a significant decreasing trend with the increase in temperature.During unidirectional cyclic tensile tests at room temperature,the yield strain of aluminum alloy specimens was slightly lower than that of unidirectional loaded specimens.Due to the plastic accumulation damage during the cyclic tensile process,the ductility of the specimens deteriorated under unidirectional cyclic loading.With the continuous increase in temperature,the yield of the specimens tended to occur earlier,and the deformation capacity changed from worse to better.The energy dissipation capacity of 6061-T4 aluminum alloy gradually decreased with the i

关 键 词：6061-T4铝合金 单向循环拉伸试验 高温 耗能 冷却方式 

分 类 号：TU395[建筑科学—结构工程]