<p>锤锻冲击由于工艺简单及高应变速率成形等特点在航空航天、能源工业等领域的零件制造中应用广泛。随着重大工程装备在强腐蚀、超真空、高低温等极端服役环境的应用，对锤锻成形零部件的服役性能要求也越来越严苛。同时锤锻成形存在能源消耗大及材料利用率低等一系列问题使得该技术的发展受制于新发展理念而开展的&ldquo;双碳&rdquo;工作部署要求。因此在锻造成形技术上寻求更加高效节能的成形工艺是锻造领域亟待解决的问题之一。近年来，众多学者通过对塑性成形工艺中振动场的利用，有效的降低了工件的成形载荷，从而达到强化材料成形性能的目的。而在锤锻冲击成形过程中，打击能量和间隔时间的变化意味着不同的振动激励。因此，通过研究锤锻冲击下锻件振动响应特性来突破传统锤锻装备的局限性，对于强化锤锻成形工艺优势以及提升锻件服役性能有着重要意义。本文以TC4钛合金为研究对象，结合物理实验与仿真模拟研究了锤锻冲击成形下锻件的力学性能及振动响应特性，澄清锻件力学性能与其振动响应之间的关联，主要研究内容如下：</p> <p>（1）通过工程实际拟定锤锻冲击实验，然后对锻件进行拉伸实验，明确了不同冲击参数对锻件各变形区常温及高温力学性能的影响规律；通过微观组织表征实验，理清了不同冲击参数下锻件晶粒尺寸大小及分布、位错密度的变化规律。</p> <p>（2）鉴于液压驱动的锤锻装备在成形过程中存在压锤等现象，本研究在物理实验基础上建立锤锻成形数值模型；然后进一步深入分析了不同冲击参数下锻件损伤值、等效应力应变、平均晶粒尺寸以及残余应力的分布特征与变化规律，揭示了锤锻冲击特性对锻件整体变形的影响规律。</p> <p>（3）根据锤锻冲击的动力学特性，建立TC4钛合金锻件冲击响应谱模型；基于有限元模态分析得到不同冲击参数下锻件各阶固有频率的最大振动加速度；通过对锻件振动响应特性分析，明确了热致软化效应、声学软化效应及应力波叠加效应对其力学性能和关键性能参数影响的主次关系。</p> <p>（4）依据冲击压缩力学理论，建立应力波传递计算模型，分析了不同冲击参数下锻件内部应力波的变化规律，探究了应力波叠加与反射效应对锻件变形的作用机制。</p> <p>本文的研究明确了锤锻冲击成形下锻件的振动响应特性对其力学性能的强化效应，为锤锻成形技术的工艺拓展以及研发高效锤锻设备提供理论依据。</p>

<p>Hammer forging impact is widely used in the manufacture of parts in the aerospace and energy industries due to the simplicity of the process and high strain rate forming. With the application of major engineering equipment in strong corrosion, ultra-vacuum, high-low temperature and other extreme service environments, the service performance requirements of hammer-forged formed parts are becoming more and more stringent. At the same time, hammer forging has a series of problems such as high energy consumption and low material utilization, which makes the development of this technology limited by the &quot;double carbon&quot; work deployment requirements under the new development concept. Therefore, the finding of more efficient and energy-saving forming process in forging forming technology is one of the urgent problems in the forging field. However, during hammer forging impact forming, the variation of blow energy and dwell time implies different vibration excitations. Thus, by investigating the vibration response characteristics of forgings under hammer forging impact to overcome the limitations of traditional hammer forging equipment, it is of key significance to strengthen the advantages of hammer forging forming process and enhance the service performance of forgings. In this paper, taking TC4 titanium alloy as the research object, the mechanical properties and vibration response characteristics of forgings under hammer forging impact forming were investigated by combining physical experiments and simulations. The correlation between the mechanical properties of forgings and their vibration response was clarified. The main research contents are as follows：</p> <p>(1) The impact tests of hammer forging were formulated through engineering actuality, and then the tensile tests were performed on the forgings. The influence laws of different impact parameters on the mechanical properties of forgings at room temperature and high temperature in each deformation areas were clarified. Through the microstructure characterization experiments, the changes laws of grain size and distribution, dislocation density of forgings under different impact parameters were elucidated.</p> <p>(2) Considering the existence of hammer pressure phenomenon in the forming process of hydraulically driven hammer forging equipment, a numerical model of hammer forging forming was established and verified by experiments. Then, the distribution characteristics and change laws of damage value, equivalent stress strain, average grain size and residual stress of forgings under different impact parameters were further analyzed. The influence law of hammer forging impact characteristics on the overall deformation of forgings was revealed.</p> <p>(3) In accordance with the kinetic characteristics of hammer forging impact, the impact response spectrum model of TC4 titanium alloy forgings was established. Based on the finite element modal analysis, the maximum vibration acceleration of the forging at each order inherent frequency was obtained for different impact parameters. Through the analysis of vibration response characteristics of forgings, the primary and secondary relationships of the effects of thermo-softening, acoustic-softening and stress-wave superposition on their mechanical properties and key performance parameters were clarified.</p> <p>(4) According to the theory of impact compression mechanics, the stress wave transmission calculation model was established and the change law of stress wave inside the forging under different impact parameters was analyzed. The mechanism of stress wave superposition and reflection effect on the deformation of forgings was also investigated.</p> <p>The research in this paper clarifies the strengthening effect of the vibration response characteristics of forgings under hammer forging impact forming on their mechanical properties, which provides a theoretical basis for the innovation of advanced hammer forging technology and the development of efficient hammer forging equipment.</p> <p>Hammer forging impact is widely used in the manufacture of parts in the aerospace and energy industries due to the simplicity of the process and high strain rate forming. With the application of major engineering equipment in strong corrosion, ultra-vacuum, high-low temperature and other extreme service environments, the service performance requirements of hammer-forged formed parts are becoming more and more stringent. At the same time, hammer forging has a series of problems such as high energy consumption and low material utilization, which makes the development of this technology limited by the &quot;double carbon&quot; work deployment requirements under the new development concept. Therefore, the finding of more efficient and energy-saving forming process in forging forming technology is one of the urgent problems in the forging field. However, during hammer forging impact forming, the variation of blow energy and dwell time implies different vibration excitations. Thus, by investigating the vibration response characteristics of forgings under hammer forging impact to overcome the limitations of traditional hammer forging equipment, it is of key significance to strengthen the advantages of hammer forging forming process and enhance the service performance of forgings. In this paper, taking TC4 titanium alloy as the research object, the mechanical properties and vibration response characteristics of forgings under hammer forging impact forming were investigated by combining physical experiments and simulations. The correlation between the mechanical properties of forgings and their vibration response was clarified. The main research contents are as follows：</p> <p>(1) The impact tests of hammer forging were formulated through engineering actuality, and then the tensile tests were performed on the forgings. The influence laws of different impact parameters on the mechanical properties of forgings at room temperature and high temperature in each deformation areas were clarified. Through the microstructure characterization experiments, the changes laws of grain size and distribution, dislocation density of forgings under different impact parameters were elucidated.</p> <p>(2) Considering the existence of hammer pressure phenomenon in the forming process of hydraulically driven hammer forging equipment, a numerical model of hammer forging forming was established and verified by experiments. Then, the distribution characteristics and change laws of damage value, equivalent stress strain, average grain size and residual stress of forgings under different impact parameters were further analyzed. The influence law of hammer forging impact characteristics on the overall deformation of forgings was revealed.</p> <p>(3) In accordance with the kinetic characteristics of hammer forging impact, the impact response spectrum model of TC4 titanium alloy forgings was established. Based on the finite element modal analysis, the maximum vibration acceleration of the forging at each order inherent frequency was obtained for different impact parameters. Through the analysis of vibration response characteristics of forgings, the primary and secondary relationships of the effects of thermo-softening, acoustic-softening and stress-wave superposition on their mechanical properties and key performance parameters were clarified.</p> <p>(4) According to the theory of impact compression mechanics, the stress wave transmission calculation model was established and the change law of stress wave inside the forging under different impact parameters was analyzed. The mechanism of stress wave superposition and reflection effect on the deformation of forgings was also investigated.</p> <p>The research in this paper clarifies the strengthening effect of the vibration response characteristics of forgings under hammer forging impact forming on their mechanical properties, which provides a theoretical basis for the innovation of advanced hammer forging technology and the development of efficient hammer forging equipment.</p>