多晶纯钴退火组织中的孪晶转变规律研究

Research annealed polycrystalline pure cobalt twinning organization change laws

摘要:

本文主要是结合X射线衍射（XRD）技术以及电子背散射衍射（EBSD）技术，对不同退火温度下的多晶纯钴的退火组织的变化规律展开研究。研究结果表明：残留的多晶纯钴面心立方（FCC）结构的晶粒内部在退火过程中形成了∑3孪晶界，而且具有这种特征的晶粒数量随退火温度改变不大，基本趋于稳定；同时，具有密排六方（HCP）结构的晶粒内部在退火过程中形成大量的71.4°/<11﹣20>特殊晶界。通过分析得知这种晶界形成的原因与FCC结构的晶粒中的∑3晶界的形成原因不同，是由FCC→HCP马氏体相变导致，即为相变孪晶。

Abstract:

This paper is the use of X-ray diffraction (XRD) techniques and electron backscatter diffraction (EBSD) technique to research the variation of polycrystalline pure cobalt tissue which is annealed at different temperatures. The results showed that:∑3 twin boundaries were observed in the retained FCC phase and we also find the number of grains having such a characteristic is not changed with annealing temperature, basically stable. Meanwhile, having a hexagonal close-packed (HCP) structure formed large grains of 71.4°/<11﹣20> special boundaries during the annealing process. Through analysis showed that the reasons and causes the formation of 71.4°/<11﹣20> special boundaries are not the same as the ∑3 twin boundaries which were formed in the retained FCC phase; 71.4°/<11﹣20> is formed as a result of phase transformation from FCC to HCP, following the Shoji-Nishiyama orientation relationship.