材料期刊网

T hezhirong01@163.com 用示差扫描量热仪研究了Co对Ti-Ni合金相变特性的影响， 以及退火和时效工艺对Ti-49.8Ni-1.0Co(原子分 数，%)合金相变行为的影响. 结果表明，Co不影响 Ti-Ni合金的相变类型，但降低其相变温度，以1.0Co分别取代 等量Ti和Ni后，该合金的马氏体相变温度分别降低了109和22 ℃. 350—450 ℃退火态Ti-49.8Ni-1.0Co合金冷却/加 热时发生A→R→M/M→R→A (A为母相，R为R相，M为马氏体) 型可逆相变；500—550 ℃退火态合金发生A→R →M/M→A型相变；600 ℃以上温度退火态 合金发生A→M/M→A 型相变. 随着时效时间的延长，300 ℃时效合金 的相变类型由A→R→M/M→R→A 向A→R/R→A 转变；400 ℃时效合金的相变类型由A→R/R→A向 A→R→M/M→R→A 再向A→R→M/M→A 转变；500 ℃时效合金的相变类型则保持 A→R→M/M→A 型不变. 给出了退火 温度及其时间和时效温度及其时间对R和M相变温度和热滞的影响规律.

The deformation characteristics of annealed Ti-49.8Ni-1.0Co (atomic percentage) alloy at room temperature were studied with differential scanning calorimetry (DSC) and tensile testing. The effects of annealing and aging processes on transformation behaviors of the alloy were systematically investigated by DSC. Ti-49.8Ni-1.0Co alloy shows superelasticity (SE) at room temperature. After replacing Ni with Co, the R phase (R) and martensitic (M) transformation temperatures, the transformation peak area, the SE stress and the SE loop area of the alloy are all decrease. The A→R→M/M→R→A (A-parent phase) type reversible transformation occurred in the 350-450℃ annealed alloy upon cooling / heating, the A→R→M/M→A type occurred in the 500-550℃ annealed alloy, and the A→M/M→A type occurred in above 600℃ annealed alloy. With increasing aging time, the transformation type of 300℃ aged alloy transforms from A→R→M/M→R→A to A→R→M/M→A, the one of 400℃ aged alloy transforms from A→R/R→A to A→R→M/M→R→A to A→R→M/M→A, and the one of 500℃ aged alloy is A→R→M/M→A constant. The influencing regularity of annealing temperature, annealing time, aging temperature and aging time on the R, M transformation temperature and temperature hysteresis were given out.