CNTs/Al复合材料应力松弛时效特性及建模研究  

Study on stress relaxation aging characterstics and modelling of CNTs/Al composite materials

作　　者：亢少明 黄遐 陈浩晟 周文彬[1] 高远 李勇[1] KANG Shao-ming;HUANG Xia;CHEN Hao-sheng;ZHOU Wen-bin;GAO Yuan;LI Yong(School of Mechanical Engineering and Automation,Beihang University,Beijing 100191,China;AVIC Manufacturing Technology Institute,Beijing 100024,China)

机构地区：[1]北京航空航天大学机械工程及自动化学院,北京100191 [2]中国航空制造技术研究院,北京100024

出　　处：《塑性工程学报》2024年第4期184-192,共9页Journal of Plasticity Engineering

基　　金：国家自然科学基金资助项目(52005020);航空科学基金资助项目(20230036051001)。

摘　　要：针对新一代航空航天用轻量化壁板结构用高比模量、比强度碳纳米管增强铝基复合材料(CNTs/Al)成形需求,研究了CNTs/Al应力松弛时效变形强化行为及其形性协同预测建模。在130℃条件下,对CNTs/AA2024开展了涵盖弹塑性初始加载条件(215 MPa、390 MPa和4%、6%)的应力松弛时效强化系列实验。结果表明,CNTs/AA2024的应力松弛曲线呈现较短的初始变速率松弛阶段(2.5 h)和稳定速率松弛阶段;进入塑性阶段后,应力松弛量未明显提高,可能来源于CNTs对位错移动的阻碍作用。在390 MPa初始应力下,材料的屈服强度随时间延长而提高,在5 h左右达到峰值时效,屈服强度为485 MPa,至16 h未出现明显过时效。在相同时效时间下,CNTs/AA2024屈服强度随着初始应力的提高而增加;塑性加载阶段,屈服强度提升效果更为明显(576 MPa),主要是由于加工硬化和位错诱导析出强化的协同作用。进一步的,建立了针对CNTs/AA2024应力松弛时效的统一本构模型,实现了其应力松弛变形、时效强化以及关键微观变量的协同预测。Aiming at the forming requirements of carbon nanotubes-reinforced aluminum matrix composites(CNTs/Al)with high specific modulus and high specific strength for the new generation of lightweight panel structures for aerospace,the stress relaxation aging deforma-tion strengthening behaviors and its collaborative predictive modeling of shape and property of CNTs/Al were investigated.A series of stress relaxation aging tests covering elastic-plastic initial loading conditions(215 MPa,390 MPa,and 4%,6%)were conducted on CNTs/AA2024 at 130℃.The results show that the stress relaxation curves of CNTs/AA2024 present a short initial variable rate relaxa-tion stage(2.5 h)and a subsequent stable rate relaxation stage.In the plastic stage,the stress relaxation amount does not increase signif-icantly,which may be due to the hindering of dislocations by CNTs.Under the initial stress of 390 MPa,the yield strength of the material increases with ageing time,reaching the peak ageing state at about 5 h,with the yield strength of 485 MPa,and no obvious over-aging oc-curs until 16 h.Under the same aging time,the yield strength of CNTs/AA2024 increases with the increase of the initial stress,and the yield strength improvement effect is more obvious(576 MPa)in the plastic loading stage,mainly due to the synergistic effects of work hardening and dislocation-induced precipitation strengthening.Furthermore,a unified constitutive model for the stress relaxation aging of CNTs/AA2024 was proposed to realize the synergistic prediction of stress relaxation deformation,aging strengthening and key microscopic variables.

关 键 词：应力松弛 本构建模 碳纳米管 铝基复材 人工时效 

分 类 号：TG146.21[一般工业技术—材料科学与工程] TG306[金属学及工艺—金属材料]