Development of the Method for the Measurement of Single Crystal Elastic Constants from Polycrystalline Specimen

本研究的目的是制作一种用于x射线衍射仪的圆盘形试样施加双轴应力的驱动器，并利用它来确定Hayakawa等人（j.p ap . cryst .）开发的多晶试样的单晶弹性常数。(1985) 513 - 518)。1。以TiNi合金为材料，制作了内径18.5mm，外径22.5 ~ 28.5mm，厚度4mm的环形执行器。时效处理使Ms温度低于0ºC， Af温度高于室温。在接近Ms的温度下，通过插入直径更大的锥形棒来扩大环的内径。在温度低于A的情况下，将圆盘状试样插入膨胀环中，然后将圆环加热至高于A的温度，冷却至室温，使圆环恢复初始形状，从而对插入的试样施加双轴压应力。通过粘贴在试样上的应变片测量应变和杨氏模量，得到了施加应力。通过改变时效处理方式改变Ms和As温度以及使用不同的执行器厚度，在室温下可获得250MPa的不同应力水平。在多晶试样上施加几种不同程度的应力并得到不同反射的d-间距后，就可以根据上述方法直接计算单晶的弹性常数。对于Fe-35wt%Ni，得到了以下数值：C_<11>=1.249 <正负> 0.100,C_<12>=0.720 <正负> 0.073,C_<44>=1.219 <正负> 0.096 [10^5MPa]，结果与单晶Fe-30Ni合金的常数（C_<11>=1.463, C_<12>=0.881, C_<44>=1.132 [10^5MPa]）相当。立方氧化锆的应用正在进行中。少

The aim of the present research was to make an actuator for exerting a biaxial stress on a disk shaped specimen for X-ray diffractometer and utilize it for a method to determine the single crystal elastic constants from a polycrystalline specimen which is developed by Hayakawa et al. (J.Appl.Cryst.. (1985) 513-518).1. Manufacturing of an actuator of TiNi shape memory alloyA ring shaped actuator (inner diameter 18.5mm, outer diameter 22.5-28.5mm, thickness 4mm) was made of TiNi alloy. A aging treatment brought the Ms temperature below 0ﾟC and Af above room temperature. At a temperature near Ms, the inner diameter of a ring was expanded by inserting a tapered rod with a larger diameter. A disk shaped specimen was inserted in the expanded ring while keeping the temperature below Ms. A subsequent heating the ring and specimen above Af and cooling to room temperature bring the ring to the initial shape, and thus exerts a biaxial compressive stress on the inserted specimen. The applied stres … More s was obtained by the strain measured through a strain gage pasted on the specimen and Young's modulus.Different level of stress up to 250MPa could be obtained at room temperature by modifying the Ms and As temperature by changing the aging treatment and by using different thickness of the actuator.2. Measurement of single crystal elastic constants from a polycrystalline specimenOnce a few different levels of stress were applied on a polycrystalline specimens and the d-spacings from various reflections were obtained, the calculation of the single crystal clastic constants were straightforward following the recipe presented by the above mentioned paper. For an Fe-35wt%Ni, the following values were obtained :C_<11>=1.249 <plus-minus> 0.100, C_<12>=0.720 <plus-minus> 0.073, C_<44>=1.219 <plus-minus> 0.096 [10^5MPa]The results compare well with the constants obtained for an Fe-30Ni alloy from a single crystal (C_<11>=1.463, C_<12>=0.881, C_<44>=1.132 [10^5MPa]).An application for a cubic zirconia is in progress. Less