Texture Control of Copper Base Shape Memory Effect Alloys

本研究旨在通过织构控制来改善铜基形状记忆合金的力学性能，研究工作分为两部分，第一部分是β相铜合金热变形织构的计算机模拟，第二部分是Cu-12 wt.% Al-5wt%Ni形状记忆合金板，根据最大外功原理，将部分约束变形条件下晶粒转动张量的唯一确定问题转化为带约束的非线性优化问题。介绍了求解该问题的数值方法，并成功地开发了定量模拟多晶金属形变织构的FORTRAN程序。利用所提出的模拟技术，对具有随机取向的Cu-12% Al-5% Ni-2% Mn-1% Ti多晶形状记忆合金板材在不同轧制条件下进行了热轧。用极图测量方法对织构进行了详细的实验研究，并考察了影响尖锐织构发展的因素。结果表明，在600 ℃左右的热轧温度下，厚度减少了85%，已经形成了相当尖锐的织构。

The present study, which is designed to improve the mechanical properties of Cu-base shape memory alloys by means of texture control, is divided into two parts; in the first one, the computer program to simulate hot-deformation textures in beta phase Cu-alloys is described and the second is concerned with the experimental examinations on textural behaviors in Cu-12wt.% Al-5wt% Ni shape memory alloy plates.The problem of unique determination of rotation tensor in crystallite under partially constrained deformation has been formulated as a nonlinear optimization problem with some constraints, based on the maximum external work principle. The numerical method for obtaining the solution of the problem has been introduced, and the FORTRAN program to quantitatively simulate the deformation textures in polycrystalline metals has been successfully developed. The proposed simulation technique applied to get the basic informations about texture control problem in Cu-base shape memory alloys.Polycrystalline Cu-base shape memory alloy plates (Cu-12 % Al -5 % Ni-2 % Mn-1 % Ti) having initially random orientations were hot-rolled in the various rolling conditions. The texture were studied experimentally in detail by means of pole figure measurements and the factors affecting sharp texture development has been examined. It turned out that the considerably sharp textures have been developed up to 85pct reduction in thickness at the hot-rolling temperature of about 600ﾟC.