摘要
采用超弹性NiTi合金棒可以使结构获得良好的自复位性能,但由于NiTi合金棒在工作中会出现不同程度的力学性能退化,致使结构的自复位与耗能能力受到削弱,因此,有必要对NiTi形状记忆合金棒材的力学性能稳定性作进一步研究。对4根经过不同热处理的Ti-50.8%Ni棒材进行常幅循环拉伸试验,研究了循环次数和不同热处理条件对棒材试件的滞回曲线形态、相变应力、弹性模量、残余应变、耗能能力等性能的影响,并对不同棒材试件的力学性能退化进行了比较分析。研究表明:常幅循环拉伸下NiTi合金棒材的弹性模量与极限应力变化相对较小,而相变应力、变形回复率以及等效阻尼比退化较为明显;材料的马氏体正相变应力相比逆相变应力降低幅度更大,且超弹性较好的NiTi合金棒材相变应力退化更明显;热处理温度过高或过低均会导致NiTi合金棒材的超弹性劣化,且棒材在循环工作中耗能能力会出现大幅下降。
Structures can obtain good self-centering performance by using superelastic NiTi alloy bars.However,due to the mechanical property degradation of NiTi alloy bars,the self-centering and energy dissipation capacity of the structure will be degraded.Therefore,it is necessary to further study the mechanical property stability of NiTi shape memory alloy bars.In this paper,the constant amplitude cyclic tensile tests were carried out on four Ti-50.8%Ni bars after different heat treatments.The effects of the number of cycles and heat treatment conditions on the hysteresis curve morphology,phase transition stress,elastic modulus,residual strain,and energy dissipation capacity of these bars were studied.The degradation of mechanical properties of different bar specimens was compared and analyzed according to the test results.The results showed that the elastic modulus and ultimate stress of NiTi alloy bars changed little in constant amplitude cyclic tensile tests,while the phase transition stress,deformation recovery rate,and equivalent damping ratio degraded significantly.The positive phase transition stress of martensite exhibited a greater reduction compared to the inverse phase transition stress,and the stress degradation of the NiTi alloy bars with better superelasticity was more obvious.Furthermore,both excessively high and low heat treatment temperatures led to superelastic deterioration of NiTi alloy bars,and their energy dissipation capacity was greatly reduced under cyclic loading.
作者
俞昊然
李维滨
YU Haoran;LI Weibin(School of Civil Engineering,Southeast University,Nanjing 211189,China;Nantong Fourth Construction Group Co.,Ltd.,Nantong 226300,China)
出处
《工业建筑》
2025年第5期152-162,共11页
Industrial Construction
关键词
形状记忆合金
力学性能退化
循环拉伸试验
热处理
超弹性
自复位
shape memory alloy
degradation of mechanical properties
cyclic tensile test
heat treatment
superelastic
self-centering
