(1. 昆明理工大學 材料科學與工程學院，昆明 650093；
2. 金屬先進凝固成形及裝備技術國家地方聯(lián)合工程實驗室，昆明 650093；
3. 云南省鈦材應用產品工程技術研究中心，楚雄 651209)
摘 要: 利用放電等離子燒結技術制備NiTi/表面多孔Ti梯度合金，研究不同燒結溫度對梯度合金微觀組織、表面孔隙特征、力學性能及體外生物活性的影響及機理。結果表明：隨著燒結溫度的升高，梯度合金組織由NiTi、α-Ti、Ni、Ti2Ni、Ni3Ti混合相逐漸轉變?yōu)閱我籒iTi和α-Ti相，內外層界面形成良好冶金結合，表面孔隙率和平均孔徑呈緩慢減小趨勢；同時抗壓強度值快速增大而彈性模量值變化不大；1000 ℃制備的梯度合金不僅具有良好的表面孔隙特征(孔隙率35.8%、平均孔徑423 μm)、較高的抗壓強度(632 MPa)、較低的彈性模量(9 GPa)及優(yōu)異的超彈性行為(超彈性恢復應變＞4%)，而且體外生物活性顯著提高。
關鍵字: NiTi梯度合金；燒結溫度；微觀組織；力學性能；體外生物活性
（1. School of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093, China;
2. National-local Joint Engineering Laboratory of Metal Advanced Solidification Forming and Equipment Technology, Kunming 650093, China;
3. Engineering Technology Research Center of Titanium Products and Application of Yunnan Province, Chuxiong 651209, China）
Abstract:NiTi/Surface porous Ti gradient alloys were prepared by spark plasma sintering (SPS) technology. The effects and mechanism of different sintering temperatures on the microstructure, surface pore characteristics, mechanical properties and in vitro biological activity of the gradient alloys were investigated. The results show that the gradient alloys are consisted of NiTi, α-Ti, Ni, Ti2Ni, Ni3Ti mixed phase and gradually transforms into NiTi and α-Ti phase with the increase of sintering temperatures. Furthermore, a stable metallurgical bonding on the internal and external interface of the alloys could be observed. Meanwhile, the porosity and average pore size of surface porous layer is in a slowly decreasing trend. As a result, the compressive strength of the alloys increases significantly, but the compressive elastic modulus of the alloys changes less. Gradient alloy sintered at 1000 ℃ not only exhibits good surface pore characteristics (35.8% porosity as well as 423 μm average pore size), higher compressive strength (632 MPa), lower the compressive elastic modulus (9 GPa) and excellent superelastic recovery strain (＞4%), but also shows good in vitro biological activity.
Key words: NiTi gradient alloy; sintering temperatures; microstructure; mechanical properties; in vitro biological activity
