冲击载荷下应变诱导高锰钢表层组织纳米化机制

MECHANISM OF STRAIN-INDUCED NANOCRYSTALLIZATION OF HADFIELD STEEL UNDER HIGH ENERGY IMPACT LOAD

利用高分辨电子显微术，对高能冲击接触加载下高锰钢摩擦表面塑变诱导纳米晶形成机制进行了研究．结果表明，冲击接触加载下，高锰钢冲击接触表面由纳米尺度奥氏体与非晶组成；位错反应和重组以及高密度李晶在奥氏体纳米化过程中起重要作用；微小李晶与层错之间或层错与位错之间的相互作用，使晶体向非晶转变.随着非晶数量增加，纳米晶尺度减小．

By means of high resolution electron microscopy, the strain induced nanocrystallization and partial amorphization of the surface layer structure of the hadfield manganese steel under high impact energy were observed and a possible mechanism was suggested. Dislocation reaction and recombination, as well as microtwin with high density play an important role in nanocrystallization. The interactions between twin and stacking fault, or dislocation and stacking fault result in the severe lattice distortion which induces the transformation of crystalline-amorphous structure. The increase in amorphous region corresponds to the decrease of the size of the nanocrystal grains.