(1. 華南理工大學(xué) 材料科學(xué)與工程學(xué)院，廣州 510640；
2. 廣州有色金屬研究院 焊接材料研究所，廣州 510651)
摘 要: 采用造孔技術(shù)結(jié)合粉末冶金燒結(jié)工藝制備多孔NiTi合金，并利用精密萬能力學(xué)性能試驗機(jī)對孔隙率為22.4%~60.6%的多孔NiTi合金樣品進(jìn)行循環(huán)壓縮實驗，以表征其壓縮力學(xué)性能及超彈性。結(jié)果表明：所制備的合金經(jīng)若干個應(yīng)力─應(yīng)變循環(huán)“訓(xùn)練”后其輸入、輸出能量可達(dá)平衡，應(yīng)變水平高達(dá)4%，線性超彈性可靠，彈性模量穩(wěn)定；循環(huán)加載條件下，殘余應(yīng)變量隨孔隙率的增加而增大，但隨循環(huán)數(shù)的增加而減小；殘余變形與其影響因素之間可用雙曲線函數(shù)關(guān)系描述。
關(guān)鍵字: 多孔NiTi合金；超彈性；殘余應(yīng)變；彈性模量
（1. School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, China;
2. Group of Welding and Soldering Technologies, Guangzhou Research Institute of Non-ferrous Metals,Guangzhou 510651, China）
Abstract:Porous NiTi alloys were fabricated by pore-forming technique and powder metallurgy sintering process, the compressive mechanical properties and superelasticity of the porous NiTi alloys with porosity ranging in 22.4%−60.6% were characterized by cyclic compression test using a versatile mechanical testing machine. The results show that the energy input balances against the energy output during cyclic loading of the porous NiTi alloy after performing several compression cycles as ‘training’, and the porous NiTi alloys exhibit reliable lineaing superelasticity and stable elastic modulus, with strain as high as 4%. The residual strain (εr) increases with increasing porosity whereas decreases with increasing number of compression cycles. The correlation between εr and other influential factors largely follows a hyperbolic trend.
Key words: porous NiTi alloys; superelasticity; residual strain; elastic modulus
