As electronic products advance toward higher integration and miniaturization, the performance demands on filament materials have increased significantly. These materials now require excellent continuous deformation processing capabilities, along with improved electrical conductivity and signal transmission stability. In response to these challenges, this study separately prepares polycrystalline copper wire and single-crystal copper wire, focusing on their distinct structural characteristics. Key microstructural aspects examined include grain morphology, recovery and recrystallization behavior, texture evolution, and twinning features. The results indicate that as the degree of deformation increases, the Schmid factor and small angle grain boundary content inside polycrystalline copper wire and single crystal copper wire decrease, while the large angle grain boundary content show an increasing trend. Moreover, this increasing trend is more pronounced in the accumulated micro wire diameter state of large deformation. Compared to polycrystalline copper wire, single crystal copper wire has a higher proportion of Schmidt factor and small angle grain boundaries. In addition, the deformation twinning structure and recovery recrystallization structure inside single crystal copper wire appear later than polycrystalline copper wire, The recovery degree of single crystal copper wire is much higher than that of polycrystalline copper wire. Due to the higher Schmid factor of <100> compared to <111>, the higher the Schmid coefficient, the stronger the deformation ability. In the state of micro-wire diameter, the main texture type of single crystal copper wire is <111> + <100>, and the main texture type of polycrystalline copper wire is <111> + <112>. Therefore, single crystal copper wire has higher deformation ability compared to polycrystalline copper wire.

To advance the utilization and development of copper-based composite wires, various samples were fabricated, including composite copper wires with Ag-Gr coated, Ag/Gr coated, and drawn Ag/Gr coatings. This study compared and analyzed the morphological characteristics, microstructure, and elemental distribution across different types of composite wires and their interfaces. The findings reveal a robust bonding interface between the composite coating and the copper wire substrate. Notably, interfaces between differing materials varied significantly, categorized either as serrated or flat. A mutual diffusion zone was observed at these interfaces. The coatings contained three primary elements: Cu, Ag, and Gr. Notably, graphene exhibited a higher propensity for diffusion within the silver coating than in the copper wire substrate. In comparison to the pure silver coating, the Ag-Gr mixed coating displayed finer grains, predominantly lath-shaped, with the presence of twinning. Macroscopic examination revealed the surface of the as-plated Ag-Gr coating to be of superior quality. The as-plated Ag/Gr coating exhibited an uneven, close-packed cell structure, which significantly improved in quality after drawing.

With the rapid advancement of the high-end electronic information industry, there is an increasing demand for metallic wires featuring ultra-fine diameters and high strength. Due to their superior strength and plastic deformability compared to pure copper wires, Cu-Ag alloy wires have attracted significant attention. In this study,Cu-20Ag alloy wires with various diameters were fabricated, and the evolution of their microstructure and twinning characteristics under large cumulative deformation was systematically investigated. The results show that the as-cast Cu-20Ag alloy rod exhibits a continuous eutectic network structure. As the wire diameter decreases, this network-like grain structure gradually transforms into fibrous grains. When the wire reaches the micron-scale, significant mutual diffusion between the Cu and Ag phases occurs, resulting in the formation of an abnormal interfaces induced by mechanical alloying. With further deformation, the Ag phase thickness is reduced, interdiffusion between Cu and Ag phases becomes more pronounced, and the interaction with twinning becomes increasingly significant. Moreover, cumulative deformation leads to a gradual refinement in both the twin width and twin boundaries within the Cu-20Ag wires. These findings provide theoretical insights for the development of ultrafine Cu-Ag wires and help to bridge the research gap in understanding the extreme deformation mechanisms of Cu-Ag alloys with high silver content.

Single crystal copper exhibits superior conductivity compared to polycrystalline copper due to its lack of internal grain boundaries, finding extensive application in the field of electronic information transmission. The hot horizontal continuous casting method, employed for the fabrication of single crystal copper rods, directly influences their production and quality. This study simulated the effects of process parameters on the temperature and solidification fields during hot horizontal continuous casting, utilizing the directional solidification method. Comparative analyses of microstructural and mechanical properties between fabricated single and polycrystalline copper rods were conducted to provide a scientific basis and technical support for the optimization and application of copper rod materials in specific fields. Findings indicate that the melt temperature minimally affects the position of the solid-liquid interface in hot continuous casting. An increase in mold temperature causes a slight outward shift in this interface, while an increase in casting speed significantly displaces it outward, raising the risks of breakage and leakage. The interior of single crystal copper rods primarily contains a sparse distribution of discrete dislocations, forming a preferred orientation pattern dominated by <100> texture, with a fracture mode of microporous growth. In contrast, polycrystalline copper rods contain numerous dislocation cells, forming <111>+<110> discrete textures, which are more varied than those in single crystal rods, leading to a ductile dimple-microporous aggregation fracture mode. The conductivity and elongation of single crystal copper rods are markedly higher than those of polycrystalline rods, thus affirming their exceptional electrical conductivity and plastic processing capabilities.

A crystal plasticity finite element model was developed for the drawing deformation of pure copper micro wire, based on rate-dependent crystal plasticity theory. The impact of wire diameter compression ratio on the micro-mechanical deformation behavior during the wire drawing process was investigated. Results indicate that the internal deformation and slip of the drawn wire are unevenly distributed, forming distinct slip and non-slip zones. Additionally, horizontal strain concentration bands develop within the drawn wire. As the wire diameter compression ratio increases, the strength of the slip systems and the extent of slip zones inside the deformation zone also increase. However, the fluctuating stress state, induced by contact pressure and frictional stress, results in a rough and uneven wire surface and diminishes the stability of the drawing process.

Cu–Ag alloy wire with different deformations and Ag contents of 1%, 2%, and 4% are prepared using vacuum continuous casting technology combined with cold drawing and intermediate annealing processes. The evolution of microstructure, electrical properties, and mechanical properties of the Cu–Ag alloy wire is investigated, and a relationship model between wire diameter, Ag content, and alloy wire properties is established. The results showed that the directionally solidified billets exhibited good elongation and are suitable for drawing fine wire. As the Ag content increased, the twinning content inside the Cu–Ag alloy wire also increased significantly. It is found through Strain++ characterization that there is non-uniform deformation within the wire, and the tensile and compressive strains that exist interactively tend to aggregate within the twins. The properties of the Cu–Ag alloy wire with different diameters varied significantly at different stages of deformation, showing a pronounced size effect below 1 mm. With decreasing wire diameter or increasing Ag content, the DC resistance, resistivity, and tensile strength of the Cu–Ag alloy wire gradually increased, while the conductivity decreased. The effect of Ag content on elongation is not significant. Statistical analysis revealed that the established performance model had high predictive accuracy and could provide references for the optimization of production processes for Cu–Ag alloy wire.

Currently, copper-based wire has been extensively applied in the information industry and for signal transmission due to its excellent performance in practice. Drawing speed, as a key parameter of the drawing process, has a significant impact on the production and quality of the wire. In this study, both simulation and experiment are performed to explore the evolution of deformation and damage behavior of copper wire and its microstructural properties during the process of multi-pass continuous drawing, with the drawing speed set to the range from 60 to 300 m/min. This provides guidance on the production and process optimization of the wire. It is revealed in the study that the surface of the pure copper wire is deformed more significantly than the core region, and that there is a rise in the equivalent strain and damage occurring at different locations in the longitudinal section of the wire as the number of passes increases. With the drawing speed increasing, the strain and damage occurring in the core region are reduced, while the damage caused by severe deformation on the surface shows nonlinearity. When the drawing speed increases, there is a significant improvement in the strength of the dominant texture component <101> in the copper wire, and the grain size of the wire is significantly refined. In the meantime, there is an increase in the density of dislocation within the wire. The severity of distortion caused to the grain tends to decrease, and the grain boundary is gradually blurred. By increasing the drawing speed, the surface quality of the wire is improved. Apart from that, there is a slight increase in the tensile strength, DC resistance and electrical resistivity of the copper wire, despite a decline in the conductivity of the wire.

The φ16 mm single crystal copper rod was prepared by heated-mold horizontal continuous casting, and the φ16 mm polycrystalline copper rod was prepared by up-casting technology. Both of them were drawn to φ0.2 mm, the conductivity, strength, elongation, and microstructure evolution of single-crystal copper wire and polycrystal copper wire were compared and analyzed. The results show that the plasticity of as-cast single-crystal copper rod is 13.94% higher than that of as-cast polycrystalline copper rod. When drawing to φ0.2 mm, a single crystal copper wire with high strength (506 MPa) and high conductivity (98.01% IACS). At the same deformation amount, the single crystal copper wire obviously deforms more slowly and has a higher plastic deformation capacity; the texture transformation of single crystal copper wire is from soft → hard orientation, selective orientation to discrete distribution, while the weave transformation of polycrystalline copper wire is from soft → hard orientation, then from hard → soft orientation, and finally stabilizes to selective orientation. The microstructural evolution of single-crystal copper wire and polycrystalline copper wire during continuous deformation was observed: dislocation entanglement into dislocation cells by slip → microstrip structure → lamellar organization → twinning organization, single-crystal copper wire appears twinning later, single-crystal copper deformation coordination ability is better than polycrystalline copper. It is found that the increase of dislocation density, the decrease of grain width and the increase of <111> texture are the main factors for the strength improvement of micro-nano pure copper wires.

采用三室真空冷型竖引连铸设备制备了线径为7.821 mm的铸态Cu-4 mass％Ag合金杆,并利用多道次连续拉拔工艺制备了变形量分别为53.38％、93.14％和98.37％的线材;分别对铸态和拉拔态的Cu-4 mass％Ag合金线材进行力学性能、电学性能测试以及微观组织分析.结果表明:铸态Cu-4 mass％Ag合金杆的抗拉强度为236 MPa、导电率为88.50％IACS,当拉拔变形量达到98.37％时,抗拉强度升高到674 MPa,提升了 185.59％,而导电率下降到81.00％IACS,仅下降了 8.47％;铸态Cu-4 mass％Ag合金杆的横截面组织为典型的"纺布"状枝晶、纵截面为"鱼骨"状枝晶,随着拉拔变形量的增加,线材在纵截面上整体结构呈现出纤维状组织,边缘部分的变形程度要比心部剧烈;当拉拔变形量达到98.37％时,产生了形变孪晶.加工硬化和细晶强化是Cu-4 mass％Ag合金线材拉拔过程中的主要强化机制.

Copper-based wire has excellent comprehensive performance and is widely used in integrated circuit packaging, electronic communication, connectors, audio and video transmission, and other fields. Based on the crystal plasticity finite element method, the crystal plasticity finite element model of multi-pass continuous drawing deformation of pure copper micro wires was established, and the reliability of the model was proved. The continuous drawing deformation behavior of micro wires under high-speed deformation and micro wire diameter scale effect was studied. The research shows that there is a fracture risk zone under the alternating action of positive and negative stress values in the deformation zone of the drawn wire. The changing drawing force and contact stress during the continuous drawing process of the wire will also reduce the stability and surface quality of the wire during the drawing process. The shear deformation and slip degree of the surface grain of the drawn wire are greater than those of the core grain, and the drawing die has a greater impact on the slip system state of the surface of the wire. With the increase in drawing passes, the mechanical characteristics inside the wire increase accordingly, and the deformation uniformity inside the grains is improved. The established model can demonstrate the deformation history characteristics and structure inheritance of the continuous wire drawing process.

采用热型水平连铸工艺制备了φ16 mm单晶铜杆坯,并对其进行了不同变形量的冷拉拔处理,采用扫描电镜(SEM)、透射电镜(TEM)、智能金属导体电阻率仪和电子万能试验机等分析了铸态和拉拔态单晶铜的组织、导电率、抗拉强度和断口形貌.结果表明:铸态单晶铜杆坯的导电率为102.2％IACS,抗拉强度为141 MPa,经总变形量为96.5％的冷拉拔变形后(φ16 mm→φ3mm),导电率高达98.86％IACS的同时,抗拉强度大幅提升至414 MPa,同铸态相比,拉拔态线材导电率仅降低了 3.3％,而抗拉强度提高了 193.6％;铸态杆坯的显微组织呈现无晶界特征,拉拔态组织为纤维晶组织;断口形貌表明铸态杆坯断口呈现扁铲状,断裂机制为微孔长大型断裂,经总变形量为96.5％的冷拉拔变形后断口横纵比变小,出现大韧窝里包含许多小韧窝的现象,断裂机制为韧窝-微孔聚集型断裂;TEM观察表明当总变形量为96.5％时,分隔位错胞块的高密度位错墙(DDWs)和微带(MBs)的数量明显增加.

This study deals with the evolution of strength and microstructure in Cu-20Ag alloy during wire drawing from an initial diameter of 7.84 mm-0.02 mm. The final wire had a strength of 1670 MPa and 53.8% of the conductivity of international annealed copper standard (IACS). Electron backscattering diffraction (EBSD) and transmission electron microscope (TEM) were used for microstructural characterization in the later stages of deformation, we found that many boundaries resulting from the lamellar structures and the occurrence of nano-twins formed in the lamellar improved the strength of the wire. When the wire diameter is less than 2.95 mm,with an essentially constant dislocation density, the strength can be related solely to strengthening boundaries by a grain size refinement. The strengthening mechanism of the wire during cumulative strain is discussed.

为获得合理的Cu-20Ag合金线材连续拉拔工艺及综合性能更为优异的线材质量,基于Deform有限元软件对Cu-20Ag合金线材多道次连续拉拔过程进行了数值模拟研究,获得了等效应力和等效应变的分布信息,利用点追踪功能分析了多道次连续拉拔过程中线材芯部沿径向到圆周表层的应力和应变的变化情况.并对通过多道次连续拉拔实验制备得到的线材进行了显微组织和断口形貌分析,获得了合金的组织演变规律.结果表明:Cu-20Ag线材表层金属的变形程度比芯部更为剧烈,且随着拉拔道次的增加,线材纵截面各处的等效应力和等效应变值都不断增大.经过多道次连续拉拔,线材纵截面的连续纤维组织近似完全平行于轴向,组织间距逐渐变小且越来越密集,线材组织的细化和均匀化程度也得到了明显增加.

The φ16 mm single-crystal copper rod billet was prepared by the heated mold horizontal continuous casting process. After cold drawing + 600 °C× 5 s annealing to φ1 mm, the annealed φ1 mm single-crystal copper processing wire was cold drawn to φ0.2 mm (φ1 mm → φ0.2 mm), and the electrical conductivity, tensile strength and microstructure evolution of single-crystal copper wire were compared and analyzed. The research shows that the conductivity of the as-cast single-crystal copper rod is 102.1% IACS, the tensile strength is 141 MPa, the conductivity is as high as 97.26% IACS, after cold drawing to φ0.2 mm, and the tensile strength is greatly increased to 506 MPa. Compared with the as-cast properties, the electrical conductivity of the as-drawn wire is only reduced by 4.7%, while the tensile strength is increased by 258.9%. The as-cast rod exhibits typical characteristics of single-crystal copper; with the increasing amount of deformation, the microstructure evolves in the following form: dislocations generated by slip entanglement into dislocation cells → microstrip structure → layered structure → twin structure. A prediction model for the strength and electrical conductivity of single-crystal copper wire was constructed. The results show that grain refinement strengthening and dislocation strengthening are the key factors affecting the strength and conductivity of single-crystal copper wire, when deformed to φ0.2 mm, and twinning strengthening is superimposed in the above strengthening mechanism.

采用三室真空冷型竖引连铸+多道次冷拉拔变形工艺制备了不同线径的Cu-20 mass％Ag合金线材,测试了合金线材在不同变形量下的导电率和抗拉强度,分析了其显微组织的演变规律.结果表明:铸态Cu-20 mass％Ag合金杆坯(φ7.84 mm)的导电率为80.3％IACS,抗拉强度为263 MPa;当拉拔变形量达到98.4％(φ1 mm),线材的导电率为69.6％IACS,抗拉强度达到889 MPa.铸态Cu-20 mass％Ag合金杆坯的共晶组织在横截面上呈现为连续的网状结构,在纵截面上呈现为鱼骨状.随着变形量的增加,Cu-20 mass％Ag合金的共晶组织沿拉拔方向形成长纤维并沿轴向排列,纤维间距逐渐减小.在拉拔变形过程中,Cu-20 mass％Ag合金的主要强化机制是位错强化和细晶强化.

为了解决当下专用食品3D打印机可打印食材种类单一的问题,课题组设计了一款可打印巧克力和面点类的通用挤出型食品3D打印机.通过SolidWorks软件设计了笛卡尔坐标系形式的机械结构,并对其滚珠丝杠螺母传动机构进行了分析计算,详细介绍了其选型过程.通过气压供料、活塞挤出的方式,实现了打印喷头的连续供料功能.针对巧克力类熔融挤出低温冷却及面点类常温挤出加热熟化的食材成型特性,设计了可实现制冷和加热切换的恒温打印平台温控系统,实现了食品3D打印成型的通用性.研究结果表明该型食品3D打印机能以连续性供料的方式打印巧克力及面点类食品,顺应了多功能发展的理念.所设计的食品3D打印机可以完成一机多用的个性化食品打印,具有一定的实用价值.

利用Simufact.Forming软件对TC4钛合金叶片的精锻过程进行了数值模拟研究,分析了叶片成形后其等效应力场、等效应变场、温度场的分布情况,研究了不同坯料温度、模具温度、上模速度、摩擦系数等工艺参数对叶片表层金属流动的影响.研究结果表明:叶片周围的毛边区域等效应力较小、等效应变较大、温度较高;最大等效应力点易出现在靠近叶尖的叶身头部、榫头与叶身的连接处、榫头头部及尾部区域;榫头区域的等效应变和温度最低,叶身中部区域的等效应变和温度较高;叶片各区域的Z方向速度方向一致,而叶尖与叶身中部之间区域的X、Y方向速度则出现正、反两个方向的变化,易导致折叠缺陷.叶片榫头区域的金属流动速度受工艺参数影响较小,其流动速度较为缓慢,接近于0;而叶身与榫头连接处附近区域的金属流动速度受工艺参数影响较大,提高坯料温度、上模速度、摩擦系数,都可使其金属流动速度增大,而模具温度的升高则会导致金属流动速度的减小.

为了预测航空发动机叶片精锻过程中所产生的最大残余应力值,在已建立好的叶片精锻有限元模型基础上,基于simufact,forming平台对TC4钛合金航空发动机叶片精锻过程进行了仿真研究,分别获得了上模速度、坯料温度、模具温度和摩擦系数等不同工艺参数组合下的叶片最大精锻残余应力值.以收集的仿真数据作为训练样本,先后建立了响应曲面模型、BP神经网络模型和GA-BP神经网络模型,并将这3种模型的预测值与仿真值进行比较.结果 表明:所建立预测模型的最大相对误差不超过6％,其中GA-BP神经网络模型预测精度最高,可对航空发动机叶片精锻最大残余应力进行有效的预测.

为获悉叶片精锻残余应力的分布情况,利用Simufact.Forming软件对TC4合金航空发动机叶片精锻过程进行了数值模拟研究.通过X射线衍射技术对叶片实体表层残余应力进行了测量,并与数值模拟结果进行对比,验证了有限元模型的合理性.通过设计正交试验优化了叶片精锻工艺,最终得到了最优工艺参数组合及不同工艺参数对叶片精锻残余应力的影响趋势.研究结果表明:航空发动机精锻叶片的残余应力主要集中在表层,当工艺性较差时,叶片前缘头、后缘头附近的高残余应力区域范围较大,开裂的风险系数较高;模具温度对叶片精锻残余应力的影响最大,上模速度、坯料温度、摩擦因子对其影响依次减小;在上模速度为40 mm·s-1、坯料温度为960℃、模具温度为300℃、摩擦因子为0.1的情况下,可以得到较小的叶片精锻残余应力.

为获得合理的100Cr6轴承钢镦粗工艺和优良的成形质量,通过simufact.forming软件对100Cr6轴承钢的镦粗过程进行数值模拟,得到坯料镦粗过程的等效应变、等效应力及温度分布等场量信息,并研究了坯料温度、上模速度、模具温度、摩擦因数等不同工艺参数对其镦粗成形的动态再结晶及晶粒尺寸等微观组织的影响.结果表明:坯料变形大的心部区域晶粒尺寸最小,坯料周边自由变形表层区域晶粒尺寸次之,与上下模具接触的坯料难变形表层区域晶粒尺寸最大;在其他条件相同的情况下,升高坯料温度,坯料平均晶粒尺寸减小,动态再结晶体积分数增大;提高上模速度,坯料平均晶粒尺寸增大,动态再结晶体积分数减小;增大摩擦因数,坯料平均晶粒尺寸减小,动态再结晶体积分数增大;升高模具温度,坯料平均晶粒尺寸减小,动态再结晶体积分数减小.