关键词: 氧化镓晶体, 各向异性, 机械性能, 脆塑性转变

Abstract: In order to explore the free cutting direction and critical cutting depth of single crystal gallium oxide crystal ultra-precision machining，the (100) crystal plane and (010) crystal plane of the single crystal gallium oxide was divided into 24 equal parts at equal angles, and nanoindentation tests with Berkovich diamond indenter were conducted, nanoindentation scratch with Cube diamond indenter tests were conducted. The critical depth of cut for brittle-plastic transformation is the largest at 120° of the (100) crystal plane, which is about 623 nm, and the critical load of brittle-plastic transformation is 29.4 mN. The critical depth of cut for brittle-plastic transformation is the cargest at 105° of the(010) crystal plane, which is about 686nm, and the critical load of brittle-plastic transition is 20.0 mN. Gallium oxide crystals have strong anisotropy, and the (010) plane anisotropy is relatively strong. Comparing the variation trends of hardness, elastic modulus, fracture toughness and relative brittle-plastic transition critical depth of cut with direction, combined with the scratch test results in various directions, it may be seen that the (010) plane of gallium oxide crystal is an easy-to-process crystal plane, and the 105° direction is the easy machining direction.

Key words: gallium oxide crystal, anisotropy, mechanics property, brittle-plastic transition