拉伸和恢復(fù)性能的影響
(1. 東北大學(xué) 材料物理與化學(xué)研究所，沈陽110004; 2. 中國科學(xué)院 金屬研究所，沈陽110016)
摘 要: 采用XRD、SEM和拉伸試驗(yàn)機(jī)對熱軋Ni47Ti44Nb9形狀記憶合金板材的織構(gòu)及其對拉伸和恢復(fù)性能的影響進(jìn)行研究，以便為改善該合金的力學(xué)和記憶性能提供理論依據(jù)。熱軋板材的織構(gòu)主要為{001}áuv0ñ和{111}áuvwñ絲，沿軋向(RD)，{001}áuv0ñ絲織構(gòu)中強(qiáng)組分向{001}á010ñ靠近，{111}áuvwñ絲織構(gòu)中的{111}á112ñ和{111}á165ñ組分較強(qiáng)；沿橫向(TD)，強(qiáng)織構(gòu)組分為{001}á010ñ和{111}á132ñ；熱軋板材經(jīng)高于再結(jié)晶溫度熱處理后，沿軋向，應(yīng)力誘發(fā)馬氏體相變臨界應(yīng)力最高，與軋向成45˚角方向的臨界應(yīng)力最低，且沿橫向拉伸斷口表面出現(xiàn)很多微裂紋；經(jīng)850 ℃熱處理后，臨界應(yīng)力隨著冷速的加快而降低，且該溫度下退火板材的織構(gòu)對可恢復(fù)應(yīng)變的影響不明顯，基本在7.0%~7.4%。
關(guān)鍵字: Ni47Ti44Nb9形狀記憶合金；織構(gòu)；拉伸性能；恢復(fù)應(yīng)變；斷裂
hot-rolled Ni47Ti44Nb9 shape memory alloy sheet
（1. Institute of Materials Physics and Chemistry, Northeastern University, Shenyang 110004, China;
2. Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China）
Abstract:The texture and its influence on tensile and recoverable properties of hot-rolled Ni47Ti44Nb9 shape memory alloy sheet were studied by XRD, SEM and tensile tester to provide theoretic basis for improving mechanical and memory properties of the alloy. The main textures of hot-rolled sheets are {001}áuv0ñ and {111}áuvwñ fibres. The strong components in {001}áuv0ñ fibre approach to {001}á010ñ component, and {111}á112ñ and {111}á165ñ components are stronger in {111}áuvwñ fibre along RD. The {001}á010ñ and {111}á132ñ are the strong components along TD; The critical stress of stress-induced martensite transformation along RD is the maximum and the minimum is along 45˚ to RD for hot-rolled sheet heat-treated at temperature higher than the recrystallization temperature, and some micro-cracks appear on the fracture surface of the specimen tensioned along TD. The critical stress decreases with increasing the cooling rate at 850 ℃, and texture has no obvious influence on the recoverable strain whose values are basically in the range of 7.0%−7.4% for sheet annealed at 850 ℃.
Key words: Ni47Ti44Nb9 shape memory alloy; texture; tensile property; recovery strain; fracture
