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本文利用原子力显微镜原位研究Mn79.5Fe15.6Cu4.9反铁磁高温形状记忆合金在升降温过程中与马氏体相变相关的表面起伏特征,同时采用X射线衍射、动态热机械分析等实验检测手段辅助分析其微观组织结构演化,从纳米尺度分析面心立方—面心四方结构相变及表面浮突产生的物理机理.实验结果表明:在升降温过程中观察到帐篷型表面浮突,由面心立方—面心四方马氏体逆相变产生的,即母相浮突,这与通常观测到的马氏体浮突不同;实验证实面心立方—面心四方马氏体逆相变具有切变特征,马氏体孪晶的逆向切变是产生帐篷型表面浮突的主要机理;测得逆孪晶切变的浮突角小于1?,远小于传统形状记忆合金的表面浮突角值,这是由于面心立方母相与面心四方马氏体相结构差异较小造成的;表面浮突随温度变化具有极好的可逆性,这是马氏体相变晶体学可逆性决定的,表明该合金具有优良的表面形貌记忆效应.
In this paper, atomic force microscopy in-situ study of Mn79.5Fe15.6Cu4.9 anti-ferromagnetic high temperature shape memory alloy during the ascending and descending temperature and martensite transformation related surface roughness characteristics, and the use of X-ray diffraction, dynamic thermo-mechanical analysis and other experiments The detection mechanism helps to analyze the evolution of the microstructure and to analyze the physical mechanism of face-centered cubic-face-centered tetragonal phase transition and surface buoyancy from the nanoscale.Experimental results show that tent-shaped surface buoyancy, It is different from the commonly observed martensite bump by the face-centered cubic-face-centered tetragonal martensitic reverse transformation, ie, the mother-phase bump. Experiments confirm that the face-centered cubic-facet square martensite reverse phase Shear deformation of the martensite twin is the main mechanism of tenting surface bursts; the bump angle of the inverse twin shear is less than 1 μ, which is much smaller than that of the traditional shape memory alloy This is due to the small difference between the face-centered cubic phase and the face-centered tetragonal martensite phase. The surface float has excellent reversibility with temperature, which is due to the fact that the martensitic transformation is reversible Sexual decisions, that Alloy having excellent surface topography memory effect.