热变形参数对47Zr-45Ti-5Al-3V合金β→α相转变的影响

Effects of Hot Deformation Parameters on β→α Phase Transformation of 47Zr-45Ti-5Al-3V Alloy

采用Gleeble 3500热模拟实验机和D/MAX-2500/PC型X射线衍射仪研究了热变形参数对47Zr-45Ti-5Al-3V合金β→α相转变的影响。结果表明,在850℃固溶处理后,该合金发生完全再结晶,再结晶晶粒尺寸为224μm,合金的组织由单一β相组成。在α+β两相区热变形过程中,该合金将发生β→α相的转变,其相变行为依赖于应变速率和变形温度。在低应变速率变形时,该合金发生了β→α相的转变;而在高应变速率变形时,该合金发生α→β相转变。在低温高应变速率变形时,该合金中析出的α相为针状。随变形温度的升高和应变速率的降低,针状α相发生球化,而且球状α相的体积分数逐渐增加。当变形温度为600℃和应变速率为10-3s-1时,针状α相完全球化。

The effects of hot deformation parameters onβ→αphase transformation of 47Zr-45Ti-5Al-3V alloy were investigated by using Gleeble 3500 thermo-mechanical simulator and D/MAX-2500/PC X-ray diffractometer.The results show that the full recrystallization occurs in the alloy after solution treatment at 850℃,and the recrystallized-grain size is measured to be 224μm.The microstructure of the alloy consists of a singleβphase after solution treatment.Theβ→αphase transformation occurs during hot deformation in theα+βphase field,which depends on the deformation temperature and strain rate.At lower strain rates,theβ→αphase transformation occurs in the alloy,whileα→βphase transformation occurs at higher strain rates.At low deformation temperature and high strain rate,the precipitatedαphase is needle-like.With increasing deformation temperature and decreasing strain rate,the needle-likeαphase becomes globular.The volume fraction of globularαphase gradually increases.At the deformation temperature of 600℃and strain rate of 10-3s-1,the needle-likeαphase is fully globularized.