中文摘要：

利用低温分解型造孔剂与梯级热等静压烧结和常规烧结的匹配工艺成功制备出了梯度孔隙率与大孔隙尺寸多孔NiTi形状记忆合金．多孔合金的孔隙率为30％—61％，孔隙平均尺寸可根据不同预处理工艺在5m-500μm之间变化，且具有较高的开孔率（最高可达85％）．所制备的径向梯度孔隙率多孔NiTi合金具有良好的力学性能，线性超弹性应变大于4％；热分析和XRD分析表明，所制备的多孔合金呈现明显的马氏体转变和逆转变特征，相变特征温度随孔隙率的提高而降低．

英文摘要：

Porous NiTi shape memory alloys with gradient porosity, large pore-size and satisfactory mechanical property were fabricated by using pore-forming agent combining with hot isostatic pressing （HIP） and conventional sintering process （CS）. The results showed that the porosity ratio and pore-size can be changed in the ranges of 30%-61% and 50-500 μm respectively under the reasonable addition amount of pore-forming agent （NH4HCO3） and sintering process. XRD and DSC proved the prepared samples exhibit multi-stage martensitic transformations, the transition temperature decreases with increasing porosity. The sample with radial gradient porosity shows good compression property and excellent linear superelasticity higher than 4%.