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Ti-5Al-2Mo-3Zr合金淬火组织为初生α相加六方马氏体α′相。α中呈现零散位错线、位错列、位错对排列及位错网络等精细结构。全位错的Burgers矢量为1/3<11(?)0>型。α′中可观察到三种孪晶形态,即多边形薄片孪晶,沿马氏体长度方向的孪晶及沿宽度方向的孪晶,均为{10_(?)1}型。在此合金中鉴定出“三孪晶取向”关系,即一片马氏体与内部孪晶及相邻马氏体片,两两互成镜像的三种取向孪晶。除正常孪晶面{10(?)1}外,还存在一个与之垂直的对称面{10(?)3}。更有甚者,这三种孪晶均与β相成Burgers关系,这对了解此合金的马氏体转变机制,提供了重要线索。
The quenched microstructure of Ti-5Al-2Mo-3Zr alloy is primary α plus hexagonal martensite α ’phase. α shows scattered dislocation lines, dislocation arrays, dislocation pairs and fine structures such as dislocation networks. All-bit-wrong Burgers vectors are 1/3 <11 (?) 0>. There are three kinds of twins observed in α ’, namely the twin of polygonal sheet, the twin along the length of martensite and the twin along the width, both of which are {10 _ (?) 1}. In this alloy, the “three-twin orientation” relationship was identified, that is, one piece of martensite and the internal twin and the adjacent martensite, each mirroring two pairs of orientation twins. In addition to the normal twin plane {10 (?) 1}, there is a perpendicular plane of symmetry {10 (?) 3}. What is more, these three kinds of twins are β-phase Burgers relationship, which understanding of the alloy martensitic transformation mechanism, providing important clues.