本文關(guān)鍵詞：SPS制備NiTi表面多孔梯度合金的組織與性能研究　出處：《昆明理工大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 鎳鈦梯度合金 燒結(jié)溫度 微觀組織演變 表面孔隙特征 力學(xué)性能

【摘要】：NiTi合金不僅具有高比強度、低彈性模量、良好耐磨耐蝕性、高抗疲勞性等優(yōu)點,而且還具有優(yōu)異形狀記憶效應(yīng)和超彈性性能,在脊椎矯形、顱骨修補、牙齒正畸及心血管支架等方面得到了廣泛應(yīng)用。但是該合金屬表面無生物活性,很難與骨組織形成長期穩(wěn)定的骨性結(jié)合。通過在NiTi合金中引入孔隙結(jié)構(gòu)形成多孔合金,不僅顯著降低了合金彈性模量,而且可以與生物硬組織形成良好匹配提高了生物活性。但是當(dāng)孔隙率高于某一水平后,多孔合金的強度下降明顯,不能滿足臨床的要求。因此,本文在前期利用SPS技術(shù)制備孔隙均勻、不含其他雜質(zhì)相的多孔NiTi合金基礎(chǔ)上,設(shè)計并制備了新型NiTi表面多孔梯度合金,其中內(nèi)層為NiTi合金、外層為多孔NiTi合金層。通過基體保證材料整體力學(xué)性能的同時,來提高它的生物活性實現(xiàn)鎳鈦醫(yī)用合金性能的多功能化。在此基礎(chǔ)上,研究了 SPS燒結(jié)溫度對NiTi表面多孔梯度合金的顯微組織、界面結(jié)合情況、孔隙特征、力學(xué)性能以及生物相容性的影響及機理。并得出以下結(jié)論:(1)利用放電等離子體燒結(jié)制備了多孔鎳鈦合金:燒結(jié)溫度在800℃～1050℃范圍較好,孔隙率隨著燒結(jié)溫度呈遞減趨勢,由51.6%下降到43.5%。利用放電等離子體燒結(jié)制備了N Ti表面多孔梯度合金:650℃時由于燒結(jié)溫度過低,合金相成分不均勻,單質(zhì)Ti、Ni相的衍射峰占主導(dǎo);隨著燒結(jié)溫度升高Ti2Ni、Ni3Ti雜峰和NiTi峰增強,單質(zhì)相峰逐漸減弱;當(dāng)燒結(jié)溫度達(dá)到750℃后,單質(zhì)相的衍射峰基本完全消失,主要由NiTi相組成。650℃時基體與多孔層界面結(jié)合較差,隨著溫度的升高,內(nèi)外界面逐漸形成穩(wěn)定的冶金結(jié)合,晶粒細(xì)化,燒結(jié)效果良好。同時溫度的提高也使孔內(nèi)壁內(nèi)部表面也逐漸變得光滑,表面多孔層的孔隙率呈緩慢下降趨勢。但是燒結(jié)溫提高到800℃后,界面區(qū)域不規(guī)整統(tǒng)一,達(dá)不到梯度合金的設(shè)計要求。(2)所制備NiTi表面多孔梯度合金壓縮彈性模量隨燒結(jié)溫度升高變化不明顯,且與人骨彈性模量非常接近;而抗壓強度隨燒結(jié)溫度升高呈顯著增大趨勢。在模擬人體體液中浸泡兩周后,致密鎳鈦合金并無任何差別,多孔鎳鈦合金和梯度合金中的多孔結(jié)構(gòu)處沉積一定的磷酸鹽顆粒。梯度合金鎳離子溶出速率在致密鎳鈦合金和多孔合金之間,且均低于人體致毒劑量。同致密鎳鈦合金、多孔鎳鈦合金相比750℃燒結(jié)溫度下制備的NiTi表面多孔梯度合金不僅具有良好的界面結(jié)合和表面孔隙特征(孔隙率46.1%、平均孔徑296μm)、較高的抗壓強度(1350MPa)及較低的彈性模量(10.1 GPa),優(yōu)異的超彈性性能(循環(huán)加載卸載27次),而且還具有一定的生物相容性。
[Abstract]:NiTi alloy not only has the advantages of high specific strength, low modulus of elasticity, good wear resistance and corrosion resistance, high fatigue resistance, but also has excellent shape memory effect and hyperelastic properties in spinal orthopedic and skull repair. Dental orthodontics and cardiovascular stents have been widely used, but the metal surface has no biological activity. It is difficult to form a long-term stable bony bond with bone tissue. By introducing pore structure into NiTi alloy to form porous alloy, not only the elastic modulus of the alloy is significantly reduced. But when the porosity is higher than a certain level, the strength of the porous alloy decreases obviously, which can not meet the clinical requirements. In this paper, a new porous NiTi alloy with uniform pores and no other impurity phase was designed and prepared by SPS technique. The inner layer is NiTi alloy and the outer layer is porous NiTi alloy layer. On the basis of this, the microstructure and interfacial bonding of SPS sintering temperature on porous gradient alloy on NiTi surface were studied. Pore characteristics. The influence of mechanical properties, biocompatibility and mechanism. The following conclusion is drawn: 1) porous Ni-Ti alloy was prepared by spark plasma sintering. The sintering temperature is better in the range of 800 鈩，

本文編號：1380675