Al-Zn-Mg-Cu合金预强化高效精确热冲压变形规律与力学性能研究  

Investigation of the Deformation Characteristics and Mechanical Properties of Al-Zn-Mg-Cu Alloy Subjected to Pre-aged Hardening Forming

作　　者：胡志力 芦俊杰[2] 魏鹏飞 华林 HU Zhili;LU Junjie;WEI Pengfei;HUA Lin(Hubei Longzhong Laboratory,Xiangyang 441000;Hubei Key Laboratory of Advanced Technology for Automotive Components,Wuhan University of Technology,Wuhan 430070;Hubei Engineering Research Center for Green Precision Material Forming,Wuhan University of Technology,Wuhan 430070)

机构地区：[1]湖北隆中实验室,襄阳441000 [2]武汉理工大学现代汽车零部件技术湖北省重点实验室,武汉430070 [3]武汉理工大学材料绿色精密成形技术与装备湖北省工程技术研究中心,武汉430070

出　　处：《机械工程学报》2025年第6期160-173,共14页Journal of Mechanical Engineering

基　　金：国家自然科学基金(52075400);湖北隆中实验室自主创新(2022ZZ-04);湖北省重点研发计划(2021BAA200);湖北省科技重大(2022AAA001)资助项目。

摘　　要：传统高强铝合金热冲压技术先成形几何结构,后热处理获得组织性能,主要存在热处理变形、精度差、工序长、效率低等问题。研究开发了一种无后续热处理短流程高效精确热冲压成形技术:预强化高效精确热冲压成形技术(Pre-aged hardening forming,PHF)。以AA7075铝合金为研究对象,进行热拉伸、埃里克森杯突等试验探究工艺参数对预强化态铝合金板料热变形行为及成形性能影响规律;通过EBSD、TEM对工艺过程中的微观组织演变进行表征,揭示PHF成形过程力学性能演变规律与强化机理。真应力-应变曲线显示预强化态铝合金板料的峰值流变应力随处理温度升高、时间延长而升高,表现出明显的加工硬化现象;预强化态铝合金板料埃里克森杯突值要高于同等试验条件下O态铝合金,具有良好的成形性能,并随预强化处理温度升高、时间增加而降低;变形量越大对成形构件力学性能增强效果越好;PHF冲压成形中相变强化与变形强化叠加作用使得成形后构件无需后续热处理即可获得满足要求的力学性能。The traditional hot stamping technique for high-strength aluminum alloys initially forms the geometric structure and obtains the microstructure properties after heat treatment,which has a number of drawbacks,including heat treatment deformation,poor precision,a long process,and low efficiency.A quick,accurate,and effective hot stamping forming process without additional heat treatment is developed:pre-aged hardening forming.Taking 7075 aluminum alloy as the research object,the influence of process parameters on the thermal deformation behavior and formability of pre-aged aluminum alloy sheet is investigated by experiments of uniaxial thermal tensile test and Erichsen test.By using EBSD and TEM to analyze the evolution of microstructure during the process,the evolution law of mechanical properties and strengthening mechanism in the forming process PHF are revealed.The peak flow stress of pre-aged aluminum alloy sheet increases with the increase in treatment temperature and duration,according to the true stress-strain curve,and it shows obvious work hardening phenomena.Pre-aged aluminum alloy sheet has a greater Erichsen test value than O-state aluminum alloy under identical test conditions and is easier to shape,and diminishes as pre-aged temperature and time rise.The larger the deformation,the better the mechanical properties of the formed components will be enhanced.In PHF stamping,the superposition of phase transformation and deformation strengthening allows the produced component to acquire the necessary mechanical characteristics without additional heat treatment.

关 键 词：7075铝合金 预强化高效精确热冲压成形技术 工艺参数影响 微观组织演变 

分 类 号：TG306[金属学及工艺—金属压力加工]