BT25钛合金连续冷却转变曲线研究  

Continuous Cooling Transformation Diagram of BT25 Titanium Alloy

作　　者：蔡钢[1] 雷旻[1,2] 万明攀[1,2] 孙捷[1,2] 刘昕[1,2] 

机构地区：[1]贵州大学,贵州贵阳550025 [2]贵州省材料结构与强度重点实验室,贵州贵阳550025

出　　处：《稀有金属材料与工程》2016年第10期2578-2582,共5页Rare Metal Materials and Engineering

基　　金：贵阳市工业攻关项目(筑科合同[2012101]2-8号);贵州省工业攻关项目(黔科合GY(2012)3002)

摘　　要：采用膨胀法测得BT25钛合金在不同冷却速度下的线膨胀曲线,同时用分段冷却方法证明了此膨胀曲线能够准确反映BT25钛合金在不同冷却速度时的相变过程,并结合物相分析(XRD)、扫描电镜(SEM)和显微硬度分析,获得了合金的连续冷却转变(CCT)曲线,研究了冷却速度对BT25钛合金相变组织演变规律的影响。结果表明:当冷速小于C_1(1~3℃·s^(-1))时,相变组织为魏氏组织;冷速大于C_2(50~100℃·s^(-1))时,组织为α"马氏体;冷速在C_1~C_2时,组织为魏氏组织和α"的混合物。并且随着冷却速度的增加,魏氏组织含量减少,而α"含量增加。合金硬度随冷却速率的增加而增加。The expanding curves of BT25 titanium alloy under different cooling rates was investigated using a dilatometry method. It is proved that the expansion method is able to measure accurately phase transformation of BT25 titanium alloy at different cooling rates. The continuous cooling transformation （CCT） diagram of this alloy was achieved by X-ray diffractometer （XRD）, scanning electron microscopy （SEM） and micro-hardness analyses. The effect of cooling rate on microstructure evolution was investigated. The results show that the Widmanstaten structure is obtained at the cooling rate less than C1 （1-3 ℃·s^-1）; a＂ phase is generated at the cooling rate greater than C2 （50 ～100℃·s^-1）. The microstructure consists of Widmanstaten structure and a＂ at the cooling rate from C1 to C2. As the cooling rate decreases, the quantity of Widmanstaten structure increases and the quantity of a＂ phase decreases. The micro-hardness of BT25 alloy declines with the cooling rate decreasing.

关 键 词：BT25钛合金 连续冷却 CCT曲线 

分 类 号：TG146.23[一般工业技术—材料科学与工程]