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用X射线衍射仪、示差扫描量热仪和拉伸实验研究了退火温度丁。。和形变温度丁。对Ti-50．8Ni-0．5V形状记忆合金丝及其弹簧的相变和形变特性的影响。结果表明：400～600℃退火态合金的室温相组成为B2和R相。冷却／加热时，350～400℃退火态合金发生A-R／R-A（A-母相，R-R相）一阶段可逆相变；450～500oC退火态合金发生A-R-M／M-R-A（M-马氏体相）两阶段可逆相变；550℃退火态合金发生A-R-M／M-A型相变；600℃退火态合金发生A-M／M-A-阶段可逆相变。随Tam升高，R相变温度先升高后降低，M相变温度先升高后趋于稳定，M相变热滞快速降低，而R相变热滞则几乎不受退火温度影响。随Ta和Tam升高，退火态Ti-50．8Ni-0．5V合金弹簧的应力诱发M临界切应力升高。

Effects of annealing temperature （ Ta, ） and deforming temperature （ Td ） on the transformation and deformation characteristics of Ti50. 8NiO. 5V （atomic fraction, % ） shape memory alloy wire and coil spring were investigated by means of Xray diffraction, differential scanning calorimetry and tensile test. The main phases of the alloy annealed at temperatures of 400-600 ~C are parent phase （ B2 ） and R phase at room temperature. The A→R/R→A （A-parent phase, R-R phase） type onestage reversible transformation occurs in the alloy annealed at 350-400 ℃ ,the A→R→M/M→R→A （M-martensite phase） type twotage transformation occurs when the alloy is annealed at 450-500℃ ,the A→R→M/M→A type transformation occurs in 550 ℃ annealed alloy, and A→M/M→A type transformation occurs in the alloy annealed at 600 ℃ upon cooling/heating. With increasing T, the R transformation temperature increases initially and then decreases,the M transformation temperature increases first and then tends to be stable, the M transformation temperature hystersis decreases and the R transformation temperature hystersis is hardly affected by Ta,. With the increase of T n and Td ,the critical shear stress for stressinduced martensitic transformation of the Ti-50.8Ni-0. 5V alloy spring increases.