有限体积法研究钛合金叶轮等温精密成形

Research on isothermal precision forming process of titanium blade wheel with finite volume method

针对钛合金叶轮形状复杂、受力状况恶劣以及钛合金材料导热率低的特点,研究了叶轮等温锻造工艺中叶片顶部形状的设计、坯料直径的选择以及工艺参数的制订等技术难点.采用有限体积法模拟了Ti-6A1-4V钛合金叶轮的等温精密成形过程,分析了成形过程中金属的流动行为和对模具的充填能力,给出了成形各阶段工件的温度场和应变速率场分布情况.模拟结果表明,等温精密锻造钛合金叶轮,不仅可以获得很好的金属流线和满意的几何形状,而且由于成形的温度和应变速率条件有利于Ti-6A1-4V材料发生超塑性变形,还可以得到分布均匀的等轴细晶组织,提高锻件的力学性能.

According to the complex shape,the badly load condition of the blade wheel and the low conductivity of titanium alloy,some difficult techniques in the isothermal forging process are researched in details including the design of the top shape of blades,the selection of the billet diameter,the decision of technological parameters.The isothermal precision forming process of a Ti-6A1-4V blade wheel is simulated with finite volume method (FVM)).The flow behavior and filling ability to die of the metal is analysis.The distributions of temperature and strain rate of the workpiece in different deforming stages are also given.The simulation result proves that good streamlines and a satisfying geometrical shape can be obtained.At the meantime,since the conditions of forging temperature and strain rate are benefit for Ti-6A1-4V to occur supper-plastic deforming,the microstructure with small size of uniform distributed isometric grains can also be archived and the mechanical performance is improved.