中文摘要：

测量了Ni51．6Mn23．4Ga25单晶的交流磁化率、电阻、有无磁场下的相变应变．结果表明该材料的马氏体相变温度为252K，相变热滞后仅为6K，自发相变应变量高达-1．15％．沿应变测量方向和垂直应变测量方向施加960KA／m的磁场，双向形状记忆的应变量分别增强到-2．35％和0．56％．分析表明该单晶的大自发相变应变量起源于内应力诱导的变体择优取向，而磁增强的相变应变量归功于外加磁场通过孪晶界移动的方式诱导的变体择优取向．

英文摘要：

The altemating-current magnetic susceptibility, resistance, martensitic transformation strain with and without a biasing magnetic field on the Ni51.6Mn23.4Ga25 single crystal was measured. It was found that the martensitic transformation occurs at about 252K, with a small thermal hysteresis of 6 K, and a large spontaneous strain of-1.15% in the [001] direction. The strain relating to the two-way shape memory effect is enhanced up to - 2.35% and 0.56% with a biasing field 960 KA/m applied along the measuring direction and perpendicular measuring direction, respectively. Investigation indicates that the large spontaneous strain originates from the preferential orientation of variants induced by the residual internal stress and the field-enhanced transformation strain is attributed to the preferential orientation of variants performed by twin boundary motion.