正电子湮没技术测量冷却方式对Zr在Ni_3Al中扩散行为的影响

Diffusive behavior of Zr in Ni_3Al measured by positron annihilation technique

测量了在Ni3Al(Zr)合金经高温均匀化处理后,在空冷和水冷条件下的正电子寿命谱。结果表明,Ni3Al(Zr)合金经高温均匀化后,随即进行空冷时,随着Zr含量的增加,正电子在合金中的寿命谱特征参数降低,捕获率K降低。表明Zr原子扩散到晶界,并在晶界偏聚。而合金经高温均匀化后水冷时,合金的正电子寿命谱特征参数随着Zr含量的增加几乎没有变化。由于冷却速度较快,Zr原子来不及扩散到晶界上,而以固溶方式存在于Ni3Al基体中。

The measurement of positron annihilation lifetime of Zr containing Ni3Al showed that the lifetime parameters of positron in Ni3Al （Zr） alloys cooled in air after homogenized at 1150℃ decreased with an increase of Zr content, which indicated that Zr atoms diffused to grain boundaries （GBs） and segregated at GBs. When alloys were cooled in water, the lifetime parameters almost kept invariable with the increase of Zr concentration, meaning that Zr atoms couldn＇t diffuse to GBs because of the rapid cooling speed, but existed in Ni3Al as solid solution.