Improvement of Toughness in B2-type Intermetallic Compounds

本研究旨在了解b2型金属间化合物的强度异常，并试图提高其韧性。得到了以下结果：观察CoTi、CoZr、CoHf、NiTi和FeTi金属间化合物强度异常是否有效。结果表明：CoTi、CoZr、Colif和NiT！显示强度异常，而Fe - Ti未显示。在伪二元合金feti - coti - niti 2中也检测了这种强度异常。通过光学显微镜和透射电子显微镜测定了CoTi单晶的有效滑移体系，结果表明，在较宽的温度和取向范围内，滑移体系的范围为(011)<001>。TEM弱观测表明<001>位错未解离成部分。提出强度异常是由<001>位错的岩心结构引起的。从有效滑移系统的角度回顾了许多b2型金属间化合物，从而表明弹性参数和APB能量的各向异性是重要的。

The present study aimed to understand the strength anomaly and to attempt to improve the toughness of B2-type intermetallic compounds. The following results were obtained.1. Whether strength anomaly is operative was observed on CoTi, CoZr, CoHf, NiTi and FeTi intermetallics. Result showed that CoTi, CoZr, Colif and NiT! displayed the strength anomaly while Fe Ti did not displayed. Tis strength anomaly was examined also in the pseudobinary alloys FeTI-CoTi-NiTi.2. Operative slip systems iri CoTi single crystals were determined by means of optical microscopy and transmission electron microscopy and shown to be(011)<001>in wide range of temperatures and orientations. Also, TEM weak observation indicated that<001>dislocation was not dissociated into partials.3. It was proposed that strength anomaly is due to core structure of a<001>dislocation.4. A number of B2-type intermetallic compounds were reviewed in terms of operative slip systems and thereby anisotropy of elastic parameters and APB energy were shown to be important.