梯度孔隙率与大孔隙尺寸NiTi形状记忆合金的制备及其相变和超弹性行为  

FABRICATION,TRANSFORMATION AND SUPERELASTICITY BEHAVIOR OF NiTi MEMORY ALLOY WITH LARGE PORE-SIZE AND GRADIENT POROSITY

作　　者：张宇鹏[1] 张新平[1] 钟志源[2] 

机构地区：[1]华南理工大学机械工程学院材料科学与技术研究所,广州510640 [2]香港城市大学物理及材料科学系

出　　处：《金属学报》2007年第11期1221-1227,共7页Acta Metallurgica Sinica

基　　金：国家自然科学基金项目50671037和50471038资助~~

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50—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.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%.

关 键 词：多孔NITI合金 梯度孔隙率 常规烧结法 马氏体相变 超弹性 

分 类 号：TB383[一般工业技术—材料科学与工程]