W-Cu20粉末板材轧制过程数值模拟与实验验证
发布时间：2018-10-22 07:01
【摘要】：钨铜合金板材既有较高的强度、硬度和较低的热膨胀系数还有良好的导电导热性,在电触头,电子封装材料和热沉材料等方面应用较为广泛。钨和铜熔点差大并且互不固溶,使得传统的铸锭轧制方法无法制备钨铜合金板材。利用粉末轧制工艺结合后续烧结工序,是制备钨铜粉末合金的一条极佳途径。并且粉末轧制具有很多优点,如生产的板材成分和组织均匀,工艺简单,生产成本低等。本文采用有限元数值模拟和实际试验相结合的方法,研究W-Cu20粉末轧制规律。以钨粉和铜粉为原料,构建W-Cu20粉末的Drucker-Prager/Cap模型,建立W-Cu20粉末轧制有限元模拟模型。将模拟值和实际试验做对比验证,认为本文中的W-Cu20粉末轧制数值模拟是可信的。根据模拟结果分析轧制过程中工艺参数对模拟结果的影响规律。对粉末轧制制备出的W-Cu20生板进行烧结,并对烧结板材的相对密度,显微组织和力学性能进行了研究。构建W-Cu20粉末的Drucker-Prager/Cap模型。首先对金属钨粉和铜粉的相貌和粒度进行了分析,然后按质量比例4:1混合制备出W-Cu20粉末。利用巴西圆盘试验、单轴压缩试验计算得到了参数d和β随相对密度变化关系。又设计压缩模具,测量粉末压缩过程中受到的轴向力和径向力随压缩应变的关系,根据相关公式计算得到了模型参数R、pa和pb随相对密度变化的关系。最后给出了Drucker-Prager/Cap关于相对密度的空间构形。利用有限元软件Abaqus建立了W-Cu20粉末轧制数值模拟模型。首先利用Abaqus自带的几何造型功能进行几何建模并合理划分网格。赋予粉末材料Drucker-Prager/Cap模型参数,建立温度-位移耦合分析步,利用FORTRAN语言编写的子程序VUSDFLD更新W-Cu20粉末轧制过程中因粉末体变形改变相对密度引起的材料属性参数的变化。有限元模拟结果发现,W-Cu20粉末轧制过程模拟值和实际值基本吻合,最大误差为4.73%,认为有限元模型的建立有效和可信。工艺参数对模拟结果影响比重依次为:轧辊缝隙、轧制速度和轧制温度。W-Cu20粉末轧制时,轧辊缝隙越大,轧制所得板材相对密度越大,粉末横向流动位移越小;轧制速度越快,所得板材相对密度越小,粉末横向位移也就越小,温度场分布越均匀;轧制温度越高,板材相对密度越大,粉末流动性越好。对粉末轧制制备的W-Cu20生坯进行液相烧结。相同轧制温度制备的生坯,烧结温度从1250℃提高到1450℃,试样的相对密度最大增幅从4.63%升高到11.87%,而制备W-Cu20合金生坯的轧制温度从80℃升高到150℃,1450℃的烧结温度对试样致密度的提高由11.87%下降到1450℃下的5.3%。1350℃下制备的板材断裂强度324MPa,硬度平均为224HV,显微组织观察表明,钨相作为基体,铜相填充在钨相孔隙中。
[Abstract]:Tungsten-copper alloy sheet has high strength, hardness and low coefficient of thermal expansion, and good conductivity and thermal conductivity. It is widely used in electric contact, electronic packaging material and heat sink material. The difference of melting point between tungsten and copper makes it impossible for traditional ingot rolling method to prepare tungsten-copper alloy sheet. It is an excellent way to prepare tungsten-copper powder alloy by powder rolling combined with subsequent sintering process. Powder rolling has many advantages, such as uniform composition and structure, simple process, low production cost and so on. In this paper, the law of W-Cu20 powder rolling is studied by means of finite element numerical simulation and practical test. Using tungsten and copper powder as raw materials, the Drucker-Prager/Cap model of W-Cu20 powder was constructed, and the finite element simulation model of W-Cu20 powder rolling was established. The numerical simulation of W-Cu20 powder rolling in this paper is proved to be credible. According to the simulation results, the influence of process parameters on the simulation results is analyzed. The W-Cu20 raw plate prepared by powder rolling was sintered, and the relative density, microstructure and mechanical properties of the sintered plate were studied. The Drucker-Prager/Cap model of W-Cu20 powder was constructed. The appearance and particle size of tungsten powder and copper powder were analyzed, and then W-Cu20 powder was prepared by mixing at 4:1. The variation of parameters d and 尾 with relative density was calculated by using Brazilian disk test and uniaxial compression test. A compression die was designed to measure the relationship between the axial and radial forces in the process of powder compression and the compressive strain. The relationship between the model parameters RPA and pb with the relative density was calculated according to the relevant formulas. Finally, the spatial configuration of the relative density of Drucker-Prager/Cap is given. The numerical simulation model of W-Cu20 powder rolling was established by using finite element software Abaqus. Firstly, the geometric modeling function of Abaqus is used to model the geometry and the mesh is divided reasonably. The parameters of Drucker-Prager/Cap model are given to the powder material, and the temperature displacement coupling analysis step is established. The change of the material property parameters caused by the change of the relative density of the powder body deformation during the rolling process of W-Cu20 powder is updated by the subprogram VUSDFLD compiled by FORTRAN language. The results of finite element simulation show that the simulated value of W-Cu20 powder rolling process is basically consistent with the actual value, and the maximum error is 4.73. It is considered that the establishment of finite element model is effective and reliable. The influence of process parameters on the simulation results is as follows: roll gap, rolling speed and rolling temperature. When W-Cu20 powder rolling, the bigger the roll gap, the greater the relative density of rolled plate, the smaller the transverse displacement of powder, the faster the rolling speed, the faster the rolling speed. The smaller the relative density of the plate, the smaller the transverse displacement of the powder and the more uniform the temperature field distribution; the higher the rolling temperature, the greater the relative density of the plate, the better the powder fluidity. The W-Cu20 billet prepared by powder rolling was sintered in liquid phase. The sintering temperature of the billet prepared at the same rolling temperature was raised from 1250 鈩，
本文编号：2286443
[Abstract]:Tungsten-copper alloy sheet has high strength, hardness and low coefficient of thermal expansion, and good conductivity and thermal conductivity. It is widely used in electric contact, electronic packaging material and heat sink material. The difference of melting point between tungsten and copper makes it impossible for traditional ingot rolling method to prepare tungsten-copper alloy sheet. It is an excellent way to prepare tungsten-copper powder alloy by powder rolling combined with subsequent sintering process. Powder rolling has many advantages, such as uniform composition and structure, simple process, low production cost and so on. In this paper, the law of W-Cu20 powder rolling is studied by means of finite element numerical simulation and practical test. Using tungsten and copper powder as raw materials, the Drucker-Prager/Cap model of W-Cu20 powder was constructed, and the finite element simulation model of W-Cu20 powder rolling was established. The numerical simulation of W-Cu20 powder rolling in this paper is proved to be credible. According to the simulation results, the influence of process parameters on the simulation results is analyzed. The W-Cu20 raw plate prepared by powder rolling was sintered, and the relative density, microstructure and mechanical properties of the sintered plate were studied. The Drucker-Prager/Cap model of W-Cu20 powder was constructed. The appearance and particle size of tungsten powder and copper powder were analyzed, and then W-Cu20 powder was prepared by mixing at 4:1. The variation of parameters d and 尾 with relative density was calculated by using Brazilian disk test and uniaxial compression test. A compression die was designed to measure the relationship between the axial and radial forces in the process of powder compression and the compressive strain. The relationship between the model parameters RPA and pb with the relative density was calculated according to the relevant formulas. Finally, the spatial configuration of the relative density of Drucker-Prager/Cap is given. The numerical simulation model of W-Cu20 powder rolling was established by using finite element software Abaqus. Firstly, the geometric modeling function of Abaqus is used to model the geometry and the mesh is divided reasonably. The parameters of Drucker-Prager/Cap model are given to the powder material, and the temperature displacement coupling analysis step is established. The change of the material property parameters caused by the change of the relative density of the powder body deformation during the rolling process of W-Cu20 powder is updated by the subprogram VUSDFLD compiled by FORTRAN language. The results of finite element simulation show that the simulated value of W-Cu20 powder rolling process is basically consistent with the actual value, and the maximum error is 4.73. It is considered that the establishment of finite element model is effective and reliable. The influence of process parameters on the simulation results is as follows: roll gap, rolling speed and rolling temperature. When W-Cu20 powder rolling, the bigger the roll gap, the greater the relative density of rolled plate, the smaller the transverse displacement of powder, the faster the rolling speed, the faster the rolling speed. The smaller the relative density of the plate, the smaller the transverse displacement of the powder and the more uniform the temperature field distribution; the higher the rolling temperature, the greater the relative density of the plate, the better the powder fluidity. The W-Cu20 billet prepared by powder rolling was sintered in liquid phase. The sintering temperature of the billet prepared at the same rolling temperature was raised from 1250 鈩，
本文编号：2286443
本文链接：https://www.wllwen.com/kejilunwen/jiagonggongyi/2286443.html
