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以NH_4HCO_3为造孔剂,利用元素粉末混合烧结法制备了多孔NiTi形状记忆合金。研究了压制压力、烧结温度和烧结时间对多孔NiTi合金孔结构的影响,并分析了其物相组成。结果表明:随压制压力的增加,平均孔径和孔隙率逐渐减小;随烧结温度提高,多孔NiTi合金的平均孔径减小、孔隙率先增加后减少,孔隙分布趋于均匀;随烧结时间延长,多孔NiTi合金的平均孔径及孔隙率先增加后减少。在造孔剂添加量50%,压制压力250 MPa,烧结温度1000℃,烧结时间6 h条件下可制备出孔结构均匀(平均孔径为314μm,孔隙率56.3%)的多孔NiTi合金,其基体相为B2(NiTi)相。
Porous NiTi shape memory alloy was prepared by elemental powder sintering with NH_4HCO_3 as pore-forming agent. The effects of pressing pressure, sintering temperature and sintering time on the pore structure of porous NiTi alloy were investigated and its phase composition was analyzed. The results show that the average pore size and porosity decrease with the increase of pressing pressure. With the increase of sintering temperature, the average pore size of porous NiTi alloy decreases, the porosity increases first and then decreases, and the pore distribution tends to be uniform. With the increase of sintering time, The average pore size and porosity of NiTi alloy first increase and then decrease. Porous NiTi alloys with uniform pore structure (average pore diameter of 314μm and porosity of 56.3%) were prepared under the conditions of 50% pore-forming agent, 250 MPa pressure, sintering temperature 1000 ℃ and sintering time 6 h. The matrix phase B2 (NiTi) phase.