(北京航空材料研究院，北京 100095)
摘 要: 根据分形几何学理论，分析了TC18钛合金不同工艺条件下的热变形微观组织。利用盒维数法计算出微观组织的分形维数，并讨论了分形维数、微观组织与变形条件之间的关系。结果表明：TC18钛合金热变形组织具有自相似性，可采用分形维数对其进行定量描述；当变形速率为0.01和0.1 mm/s时，在相变点以上随着温度增加，晶粒尺寸增大，分形维数减小；当变形速率为1 mm/s时，随着温度增加，晶粒尺寸先减小后增大，分形维数先增大后减小；当变形速率为10 mm/s时，随着温度增加，晶粒尺寸先增大后减小，分形维数先减小后增大；这是晶粒长大和再结晶相互影响的结果。
关键字: TC18钛合金；分形；微观组织；晶粒；再结晶
（Beijing Institute of Aeronautical Materials, Beijing 100095, China）
Abstract:The fractal theory was applied to analyze the hot deformation microstructure of TC18 alloy under different technological conditions. Box Counting Method was used to calculate the fractal dimension of microstructure. The influence of processing parameters on fractal dimension and microstructure was studied. The results show that the shapes of hot deformation microstructure are self-similar and can be quantitatively described by fractal dimension. When the strain rates are 0.01 and 0.1 mm/s, the fractal dimension decreases with increasing deformation temperature above transformation point. When the strain rate is 1 mm/s, the fractal dimension increases and then decreases with increasing deformation temperature. While the strain rate is 10 m/s, the fractal dimension decreases and then increases with increasing deformation temperature, which is caused by grain growth and recrystallization.
Key words: TC18 alloy; fractal; microstructure; grain; recrystallization
