(江蘇大學(xué) 材料科學(xué)與工程學(xué)院，鎮(zhèn)江 212013)
摘 要: 通過恢復(fù)率實驗、拉伸實驗和顯微組織分析，研究冷軋變形對Ni-43.5Ti-0.5V形狀記憶合金超彈性和顯微組織的影響。結(jié)果表明：冷軋變形對NiTiV形狀記憶合金超彈性具有顯著影響。隨變形量的增加，合金超彈性呈現(xiàn)先增加后減小的變化規(guī)律。當(dāng)變形量大于15.4%后，大量位錯產(chǎn)生，馬氏體變體和形變孿晶組織增多且分布致密，起到強化母相、抑制滑移變形的作用，使合金超彈性顯著提高。當(dāng)變形量大于29.1%時，劇烈的組織畸變導(dǎo)致出現(xiàn)過飽和的高密度位錯，促使組織非晶化，超彈性開始減小。當(dāng)變形量在23%~25%范圍內(nèi)變化時，合金獲得最佳的非線性超彈性。單獨依靠冷軋變形不能使NiTiV合金呈現(xiàn)完全非線性超彈性。另外，恢復(fù)率實驗?zāi)軌蚋纳坪辖鸬某瑥椥裕l(fā)現(xiàn)了超彈性的穩(wěn)定性變化規(guī)律。
關(guān)鍵字: Ni-43.5Ti-0.5V合金；形狀記憶合金；冷軋變形；超彈性；顯微組織
（School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013, China）
Abstract:The effects of cold deformation on the superelasticity and microstructure of Ni-43.5Ti-0.5V shape memory alloys (SMA) were investigated by recovery rate test, tensile test and microstructure observation. The results indicate that cold deformation has an evidence influence on the superelasticity of NiTiV SMA. With the increase of the deformation, the superelasticity of the alloy increases first and then decreases. When the deformation is more than 15.4%, a large number of dislocation appears, and the microstructures of martensite variants and deformation twins increase with their compacted distribution, which can strengthen the parent phase, inhibit slip deformation and make the superelasticity of the alloy improved significantly. When the deformation is more than 29.1%, the serious distortion of microstructure makes the supersaturated high density dislocation generated, which promotes the microstructure to turn to the amorphous. The superelasticity of the alloy begins to decrease. When deformation is in the range of 23%-25%, the best non-linear superelasticity of the alloy can be obtained. In a word, non-linear superelasticity of the alloy cannot be obtained only under the condition of cold deformation. In addition, the recovery rate test can improve the superelasticity of the alloy and the variation of the stability of superelasticity was found.
Key words: Ni-43.5Ti-0.5V alloy; shape memory alloy; cold deformation; superelasticity; microstructure
