TB17钛合金两相区等温时效析出行为研究

Study on Isothermal Aging Precipitation Behavior of TB17 Titanium Alloy in α+β Region

摘要:

采用X射线衍射(XRD)、场发射扫描电子显微镜(FESEM)和透射电子显微镜(TEM)研究了亚稳β钛合金TB17在α+β两相区固溶处理后的等温时效析出行为，并分析了次生α相的析出位置、尺寸、形态。结果表明：TB17钛合金在350 ℃等温时效时，发生β→ω相变，ω相呈椭圆状，尺寸在3~5 nm之间；在450 ℃和550 ℃等温时效过程中，主要发生β→α相变。α相首先在亚晶界和亚晶缺陷处形核并长大，最后形成细小的棒状α相，并且两相区固溶时所保留的大量亚晶界加快了时效过程中次生α相的析出响应。

Abstract:

X-ray diffraction(XRD), field emission scanning electron microscope(FESEM) and transmission electron microscope(TEM) techniques were used to study the isothermal aging behavior of the metastable β-titanium alloy TB17 after solution treatment in the α+β phase region. The precipitation location, size and morphology of secondary α phase were analyzed. The results show that when aging at 350 ℃, the β→ω phase has taken place, and the ω phase is elliptical in size between 3 nm and 5 nm. When aging at 450 ℃ and 550 ℃, the β→α transformation mainly occurs. The α phase first nucleates and grows at the subgrain boundary and the subgrain defects, and finally forms a fine lamellar α phase, and due to the existence of a large number of subcrystals, the precipitation response time during aging is reduced.