(1. 國標(北京)檢驗認證有限公司，北京 100088；
2. 國合通用測試評價認證股份公司，北京 100088；
3. 有研科技集團有限公司 國家有色金屬及電子材料分析測試中心，北京 100088)
摘 要: 采用掃描電子顯微分析(SEM)、電子背散射衍射分析(EBSD)、透射電子顯微分析(TEM)、高分辨電子顯微分析(HRTEM)、高角度環(huán)形暗場-掃描透射(HAADF-STEM)等技術(shù)手段，對NiTi40(60%Ni+40%Ti，質(zhì)量分數(shù))合金淬火態(tài)樣品的微觀組織結(jié)構(gòu)進行分析。結(jié)果表明：NiTi40合金在950 ℃、150 min固溶水冷和1050 ℃、150 min固溶水冷的硬度值相近，為60~61 HRC，但微觀組織結(jié)構(gòu)有顯著的區(qū)別。經(jīng)950 ℃固溶水冷后，合金中的粗大第二相主要為NiTi2和Ni3Ti相，還有少量和NiTi2相互伴生的TiC相；經(jīng)1050 ℃固溶水冷后，合金中的Ni3Ti相接近完全回溶的，粗大第二相主要為相互伴生的NiTi2及TiC相。隨著固溶溫度的升高，合金的晶粒尺寸明顯增大，合金晶界處的小晶粒在1050 ℃固溶時基本消失。經(jīng)950 ℃固溶處理，晶內(nèi)析出相主要為10~20 nm的Ni4Ti3相；經(jīng)1050 ℃固溶處理，晶內(nèi)析出相主要為幾十至幾百納米的Ni4Ti3相。
關(guān)鍵字: NiTi40合金；固溶處理；電子顯微學(xué)分析；Ni4Ti3相
（1. Guobiao (Beijing) Testing and Certification Co., Ltd, Beijing 100088, China;
2. China United Test and Certification Co., Ltd., Beijing 100088, China;
3. National Center of Analysis and Testing for Nonferrous Metals and Electronic Materials, General Research Institute for Nonferrous Metals Group Co., Ltd, Beijing 100088, China）
Abstract:The microstructure of the quenched samples NiTi40(60%Ni+40%Ti, mass fraction) alloys was analyzed by means of scanning electron microscopy(SEM), electron backscatter diffraction(EBSD), transmission electron microscopy(TEM), high-resolution transmission electron microscopy(HRTEM) and high angle annular dark field-scanning transmission electron microscopy (HAADF-STEM). The results show that the hardness values of NiTi40 alloys after solution treatment at 950 ℃ and 1050 ℃ for 150 min are equivalent, about 60-61 HRC, but the microstructure is significantly different. After solution treatment at 950 ℃, the alloy is mainly comprised of NiTi matrix, NiTi2 and Ni3Ti precipitates, NiTi2 and TiC mutually co-existed. After solution treatment at 1050 ℃, Ni3Ti phase is completely dissolved into the matrix, and the second phase is mainly NiTi2 and TiC phase associated with each other. When the solution temperature increases, the grain size of the alloy increases significantly, and the small grains at the grain boundary of the alloy disappear substantially after solution treatment at 1050 ℃. After solution treatment at 950 ℃, the precipitation in the crystal is mainly 10-20 nm Ni4Ti3 phase, while intracrystalline precipitates are mainly dozens to hundreds of nanometer Ni4Ti3 phase after solution treatment at 1050 ℃.
Key words: NiTi40 alloy; solution treatment; electron microscopic analysis; Ni4Ti3
