Ni含量对激冷贫镍TiNi形状记忆合金薄带相变行为的影

用激冷甩带法制备了Til-xNix(x=45％～49.8％)(原子分数)形状记忆合金(SMA)薄带,用示差扫描量热仪研究了Ni含量对铸态及450℃、500℃退火态TiNi SMA薄带相变行为的影响.结果表明,冷却/加热时,铸态和退火态Ti1-xNix(x=45％～49％)SMA薄带发生A→M/M→A一阶马氏体相变;当Ni含量为49.8％时,铸态和退火态TiNi SMA薄带冷却时发生A→ R→M两阶段相变,加热时发生M→A一阶段相变.随Ni含量增加,TiNi SMA薄带马氏体正、逆相变温度范围先增大后减小,Ni含量为48％时相变温度范围最宽.退火态比铸态TiNi SMA薄带相变温度范围窄.随Ni含量增加,TiNi SMA薄带马氏体正、逆相变温度升高,相变热滞增大.当Ni含量为49％时,SMA薄带的马氏体相变温度达最大值,当Ni含量为49.8％时马氏体相变温度迅速下降.

Effect of Ni Content on Phase Transformation Behavior of Chilled Ni-poor TiNi Shape Memory Alloy Ribbons

The Ti1-xNix (x=45 ％-49.8％) (atom fraction) shape memory alloy (SMA) ribbons were fabricated by melt spinning process.Effect of Ni content on transformation behavior of as-cast and 450 ℃,500 ℃ annealed TiNi SMA ribbons were investigated by differential scanning calorimetry.The results showed that the A→M/M →A one-stage martensitic transformation occurs upon cooling and heating in as-cast and annealed Ti1-xNix (x=45 ％-49 ％)SMA ribbons.When Ni content is 49.8 ％,the A→R→M two-stage martensitic transformation occurs upon cooling,and M→A one-stage martensitic transformation occurs upon heating in as-cast and annealed TiNi SMA ribbons.With the increasing Ni content,the temperature range of martensitic transformation upon cooling and reverse martensitic transformation upon heating in TiNi SMA ribbons widens first and then narrows,and reaches the maximum when Ni content is 48％.The martensitic transformation temperature range in the annealed alloy ribbons is narrower than that in as-cast TiNi SMA ribbons.With increasing Ni content,the martensitic and reverse martensitic transformation temperature and temperature hysteresis of TiNi SMA ribbons increase.When Ni content is 49％,the martensitic transformation temperature of SMA ribbons reaches the maximum.When Ni content is 49.8％,the martensitic transformation temperature decreases drastically.