低功率超声处理对LC9合金初生晶粒的影响

以超声波输出功率密度、处理时间、熔体施振温度和铸型预热温度为研究因素,对LC9合金熔体施加低功率超声振动进行了试验研究。结果表明,通过控制低功率超声熔体处理参数与凝固条件,可以制备出初生相为球状或细小颗粒状晶体的LC9合金;功率密度在0～5W/cm2范围内,随着功率密度的增大,初生晶粒逐渐细化,但功率密度大于5W/cm2后,初生晶粒大小不再发生明显变化;随着搅拌时间的增加或施振温度的提高,初生晶粒尺寸先减小后增大,其转折点分别为45s和660℃;在室温～450℃的范围内,随着铸型预热温度的增加,晶粒尺寸迅速增大,当预热温度高于300℃时,超声波所起的晶粒球化效果被削弱。

Influences of Melt-Treatment with Low Power Ultrasonic on Primary Phase in LC9 Alloy

Effects of melt-treatment with low power ultrasonic,such as output power density,stirring time,ultrasonic vibration temperature and mould pre-heating temperature on microstructure of LC9 alloy were investigated.The results show that LC9 alloy with spherical or granular primary grain can be prepared by controlling parameters of melt-treatment with low power ultrasonic and solidification conditions.The size of primary phase tends to be decreased with increasing in ultrasonic power density within 0～5 W/cm2.With ultrasonic power density more than 5 W/cm2,the grain size change can be ignored.With the increase of stirring time or ultrasonic vibration temperature,grain size is decreased firstly,and then increased,and critical value of stirring time and ultrasonic vibration temperature is 45 s and 660 ℃,respectively.The grain size is increased rapidly with increasing in the preheating temperature of mold in range of room temperature to 450 ℃.The spheroidization effect of ultrasonic is weaken when the preheating temperature is higher than 300 ℃.