应变对两相区固溶处理Ti-55531合金室温压缩变形机制的影响

使用Gleeble3800热模拟试验机和6.3MN锻造模拟试验机对两相区固溶处理Ti-55531合金进行室温压缩变形实验,运用SEM、XRD和TEM分析变形组织,研究应变对两相区固溶处理Ti-55531合金室温压缩变形机制的影响。结果表明,两相区固溶处理Ti-55531合金组织由初生αp相和残余βr相组成,αp相的硬度低于βr相;当室温压缩工程应变量为8%~10%时,合金位错主要集中于αp相中;随着应变的增加,αp相中的位错密度增大,当工程应变量增大到20%时,大量位错在αp相与βr相的相界面处聚集,αp相内形成严重的位错塞积和位错缠结,βr相中滑移系开动的数量也逐渐增多;当工程应变量增大到30%时,βr相中也出现了位错塞积和位错缠结;应变量继续增大,当工程应变量增大到60%时,等轴的初生αp相沿变形方向被拉长,同时αp相和βr相中均出现大量位错胞。

Design of an Enhanced Sensitivity FBG Strain Sensor and Application in Highway Bridge Engineering

The theoretical design method of enhanced sensitivity fiber grating （FBG） strain sensors was given, and moreover high qualified strain sensors were developed and fabricated, whose sensing properties were good for practical applications. The strain sensor with cylindrical shell encapsulation contained three tubular structures, due to the uneven surface structure, in the area of the strain concentration, improving the sensitivity. It could achieve the embedment strain measurement and surface measurement and had the advantages of the easy installation. The good agreement was obtained between the measurements and theoretical simulation results. After each calibration test, twenty-four FBG strain sensors and six FBG temperature compensation sensors have been installed on the undersurface of the box girder of Diaoshuiyan bridge in Yongtaiwen highway. Finally, we built up a long-term structure health system for the highway bridge.