(陜西理工大學(xué) 材料科學(xué)與工程學(xué)院，漢中 723001)
摘 要: 用拉伸實驗研究經(jīng)600 ℃時效1~50 h后，時效時間tag和應(yīng)力-應(yīng)變循環(huán)對Ti-50.8Ni-0.1Zr形狀記憶合金超彈性(SE)的影響。結(jié)果表明：600 ℃時效處理后Ti-50.8Ni-0.1Zr合金具有較高的強度和良好的塑性。隨tag延長，600 ℃時效態(tài)合金的抗拉強度Rm、斷后伸長率A、應(yīng)力誘發(fā)馬氏體相變臨界應(yīng)力σM和能耗ΔW降低，殘余應(yīng)變εR先上升后下降。隨著應(yīng)力-應(yīng)變循環(huán)次數(shù)增加，600 ℃時效1~50 h的合金由部分非線性超彈性逐漸轉(zhuǎn)變?yōu)橥耆€性超彈性，ΔW和εR均逐漸降低并趨于穩(wěn)定。要使600 ℃時效態(tài)Ti-50.8Ni-0.1Zr合金獲得良好的SE特性，tag應(yīng)小于20 h；要使該時效態(tài)合金獲得穩(wěn)定的SE特性，應(yīng)對其進行不少于10次的預(yù)應(yīng)力-應(yīng)變循環(huán)。
關(guān)鍵字: Ti-Ni-Zr合金；時效時間；超彈性；應(yīng)力-應(yīng)變循環(huán)
（School of Materials Science and Engineering, Shaanxi University of Technology, Hanzhong 723001, China）
Abstract:The effects of aging time (tag) and stress-strain cycle on the superelasticity (SE) of Ti-50.8Ni-0.1Zr shape memory alloy aged at 600 ℃ for 1-50 h were investigated by the tensile test. The results show that the Ti-50.8Ni-0.1Zr alloy is of high strength and good ductility after aging treatment. The tensile strength Rm, percentage elongation A, critical stress σM for stress-induced martensite and energy dissipation ΔW of Ti-50.8Ni-0.1Zr alloy decrease gradually, while residual strain εR increases firstly and then decreases with increasing tag. With increasing stress-strain cycle number, the Ti-50.8Ni-0.1Zr alloy aged at 600 ℃ for 1-50 h transforms from incompletely nonlinear superelasticity to linear-like superelasticity, and the ΔW and εR of the alloy decrease gradually and tend to stability. In order to make 600 ℃ aged Ti-50.8Ni-0.1Zr alloy get excellent SE, the tag should be less than 20 h, and to make the alloy get stable SE, it should be subjected to a prestress-strain cycle of not less than 10 times.
Key words: Ti-Ni-Zr alloy; aging time; superelasticity; stress-strain cycling
