振动对金属枝晶凝固固-液界面形貌、组织和性能的影响

在 Bridgman 法金属枝晶凝固过程中,引入凝固系统不同共振阶次的纵向稳态正弦振动,研究振动对金属枝晶固-液界面形貌、组织和力学性能的影响。实验发现振动作用时间与振动频率对凝固过程的影响具有相同的重要性,同样的振动时间,一阶共振频率振动使固-液界面枝晶破断,而三阶共振则使其细化.实验也揭示了凝固全过程中施加一阶共振频率振动,组织中出现竹节状周期振动条纹,使力学性能下降,而引入其它阶的共振频率振动则使力学性能提高。

INFLUENCE OF VIBRATION ON THE MORPHOLOGY OF SOLID-LIQUID INTERFACE,STRUCTURE AND PROPERTY DURING DENDRITIC SOLIDIFICATION OF METALS

During dendritic solidification of metal by the Bridgman methoda stable longitudinal sinusoidal vibration with different order of resonant fre-quencys have been applied.The influence of vibration on the morphology ofsolid-liquid interface,structure and mechanical properties of metallic dendritewere determined.It is found that the time and frequency of vibration may beequally important to solidification.The first order resonant frequency of solifi-cation system makes dendritic stocks of S-L interface broken and the thirdmakes it fined at the same vibrational time.When the vibration with first orderresonant frequency has been used in whole process of solidification,severalperiodic vibrational streaks like bamboo joint in the structure are discovered.Itdecreases the mechanical properties.If the other resonant frequency is introducedthe dendritic grain is fined and the mechanical properties are improved.