摘要
通过高精度膨胀法研究了固溶态Ti-1300合金在400~700℃等温条件下相变动力学。研究表明:固溶态Ti-1300合金中亚稳β相的分解动力学可用Johnson-Mehl-Avrami(JMA)方程表征,并获得400~700℃温度范围内JMA方程的特征参数K和n,一定程度上反映了合金中亚稳β相的分解机制。当Ti-1300合金在400~420℃时效时,亚稳β相的分解方式主要为βm→β′+β→α+β;当合金在500~700℃时效时,亚稳β相的分解方式主要为βm→α+β;同时在等温条件下,时效初期α相的形核率较快,且含量迅速增加,后期达到一定量后保持稳定。根据计算和试验结果,得到了Ti-1300合金在500~700℃等温条件下亚稳β相的分解的TTT曲线,鼻尖温度约为600℃。
Phase transformation kinetics of Ti-1300 alloy after solution treatment were investigated under isothermal conditions in the temperature range of 400°C to 700°C by dilatometric method.The decomposition kinetic equation of metastableβphase in the alloy was constructed under isothermal conditions by analyzing the experimental data in the theoretical frame of the Johnson-Mehl-Avrami(JMA)theory.The different values of K and n parameters were obtained in the temperature range of 400°C to 420°C and 500°C to 700°C,indicating that the mechanism of the phase transformation is different in different temperature ranges.The decomposition mechanism of metastableβphase isβm→β′+β→α+βat the temperature of 400°C to 420°C,whereas the decomposition mechanism of metastableβphase isβm→α+βat the temperature of 500°C to 700°C.When the metastableβphase of Ti-1300 alloy was annealed isothermally at a given temperature,the amount ofαphase increases firstly,and then reaches a stable value with increasing the holding time.Based on calculation and experimental results,time-temperature-transformation diagrams(TTT diagram)of Ti-1300 alloys were plotted for the metastableβphase decomposition under isothermal conditions from 500°C to 700°C.And the nose temperature of the TTT diagram of the alloy is around 600°C for the Ti-1300 alloys.
作者
万明攀
曾玉金
谭元标
黄朝文
赵永庆
Wan Mingpan;Zeng Yujin;Tan Yuanbiao;Huang Chaowen;Zhao Yongqing(Guizhou University,Guiyang 550025,China;Northwest Institute for Nonferrous Metal Research,Xi’an 710016,China)
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2019年第12期3855-3862,共8页
Rare Metal Materials and Engineering
基金
National Natural Science Foundation of China(51401058)
Science and Technology Cooperative Foundation of Guizhou Province([2015]7655)
Youth Growth Project of Guizhou Education Department([2016]122)
