Quantitative analysis of ω-β phase transformation at 131 K enhanced by electron irradiation using a recent electron microscopy

ω-Ti合金在时效、应力和冷却过程中发生β相变。由于ω相晶的出现影响了合金的物理性能，因此从工业角度对β-ω相变进行了研究，并阐明了相变机理。由于相变已被应用于智能材料的制造，其精确控制对其应用具有重要意义，因此，本工作计划收集大量用于定量分析相变行为的数据。(1)研究了131K冷却形成的非晶态ω相晶体在四种不同条件下的电子辐照湮没行为。实验是在131K下用原位观测技术进行的。在电视-录像机系统中记录了这一过程，并确定了湮灭的开始和结束时间。湮灭…的两个不同起源更多地考虑了电子辐照引起的S；温升和辐射促进了扩散。理论上估计的温升小于1度，但没有考虑文献中提到的样品表面污染对温升的影响。由于试件表面普遍存在污染，因此考虑污染的影响成为一个问题。(2)在β-Ti合金中，存在β-ω-α相变序列。为了定量地理解这一过程，计划使用EELS技术来澄清每个相的电子态。每道工序都采用两步时效的方法。在第二个过程中，不是ω-α相变，而是ω向新相变，出现了新相。用电子衍射谱和高分辨电子显微镜对新相的晶体结构进行了研究，但尚未明确其结构。本工作的结果表明，在定量分析β-ω-α相变之前，存在两个问题。较少

ω-phase transformation in β-Ti alloys occurs due to aging, stressing and cooling. Since appearance of ω-phase crystals affects physical properties of the alloys, the phase transformation has been investigated on the industrial viewpoint and to clarify the phase transformation mechanism.In the present work, a collection of data for quantitative analysis of β-ω phase transformation behavior has been planned, because phase transformations have been applied for making intelligent materials and their precise controlling is important for the applications. The following two experiments have been carried out:(1)Annihilation behavior of ahtermal ω-phase crystals, formed by cooling at 131 K was investigated under electron irradiations with four different conditions. The experiments have been carried out at 131 K using in-situ observation technique. The processes were recorded in TV-VTR system and starting and finishing times of annihilations were determined. Two different origins of annihilation … More s due to electron irradiation have been considered; temperature-rise and radiation enhanced diffusion. Theoretically estimated temperature-rise was less than 1 degree, but the estimation did not considered effects of contamination of specimen surface, which affects the temperature-rise, as mentioned in literatures. Since specimen surfaces are generally contaminated, it becomes a problem to consider effects of contamination.(2)In β-Ti alloys, β-ω-α phase transformation sequence occurs. It was planned to clarify electron states of each phase using EELS technique for understanding the process quantitatively. A two-steps aging method was adopted to occur each process. In the second process, instead of ω-α phase transformation, ω to a new phase transformation occurs ; a new phase appears. The crystal structure of new phase has been investigated using electron diffraction pattern analysis and HREM method, but the structure has not been clarified.The results obtained in the present work indicate that two problems exist prior to the quantitative analysis of β-ω-α phase transformation. Less