摘要
研究冷变形与退火对Ti50Ni45Cu5（原子数分数,%）合金组织及性能的影响。研究结果表明：冷变形使片状马氏体变细,合金强度增加,使合金的马氏体相变温度和逆马氏体相变温度降低,且冷变形越大,相变温度降低越多;马氏体转变开始温度Ms随着母相B2晶粒尺寸减小而降低,利用热力学推导得出了Ms与母相B2晶粒尺寸关系式。经35%冷变形400℃退火1 h后,合金具有优良的综合性能,其马氏体转变开始温度Ms为45.2℃,马氏体转变终了温度Mf为10.3℃,逆转变开始温度As为49.0℃,逆转变终了温度Af为80.0℃,抗拉强度为1 198.29MPa,伸长率为7.9%。冷变形＋400℃/1 h退火Ti50Ni45Cu5合金的马氏体片细小,马氏体孪晶亚结构增多,内耗峰增高。合金在变温过程中发生B2-B19′相变,在应变振幅为2×10-5,振动频率为0.5~4.0 Hz,变温速率为2 K/min时产生内耗峰,内耗峰位置与振动频率无关,峰高随着测量频率的增加而降低,为热诱导相变内耗机制。相变温度降低,内耗峰位降低。
The influence of cold deformation and annealing on microstructure and properties of Ti50Ni45Cu5（at%） alloy were investigated. The results show that the martensite plate becomes smaller and the tensile strength of alloy increases during the cold deformation. Meanwhile, the martensite phase transformation temperatures and the reverse transformation temperatures of alloy decrease during the cold deformation. And the more cold deformation, the lower phase transition temperatures. The martensite start transformation temperature（Ms） reduces when the grain size of parent phase B2 decreases. The relationship of the martensite start transformation temperature（Ms） and the grain size of parent phase B2 is deduced by thermodynamics. The Ti50Ni45Cu5 alloy with 35% cold deformation and 400 ℃/1 h annealed has excellent comprehensive performance. The martensite start transformation temperature（Ms） and martensite end transformation temperature（Mf） are 45.2 ℃ and 10.3 ℃, respectively. Meanwhile, the reverse start transformation temperature（As） and reverse end transformation temperature（Af） are 49.0 ℃ and 80.0 ℃, respectively. The tensile strength of the alloy is 1 198.29 MPa and the elongation is 7.9%. The martensite plate of Ti50Ni45Cu5 alloy with cold deformation and 400 ℃/1 h annealing is small and the martensite twin structure increases, and then the height of internal friction peak increases. The phase transformation B2-B19′ occurs in the alloy when the temperatures change. The internal friction peak is found when the strain amplitude is 2×10-5, the vibrational frequencies are 0.5-4.0 Hz and variable temperature rate is 2 K/min. The position of internal friction peak has nothing to do with vibration frequency, but the height of peak reduces with the increase of the measurement frequencies, which belongs to the phase transformation mechanism of internal friction induced by thermal. The phase transition temperature is reduced, which reduces the position of internal friction peak.
出处
《中南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2014年第5期1437-1442,共6页
Journal of Central South University:Science and Technology
基金
总装预研项目(LH201236)
