The formulation of nanocrystallinc NiTi shape memory alloys has potential effects in mechanical stimulation and medical im- plantology. The present work elucidates the effect of milling time on the product＇s structur...The formulation of nanocrystallinc NiTi shape memory alloys has potential effects in mechanical stimulation and medical im- plantology. The present work elucidates the effect of milling time on the product＇s structural characteristics, chemical composition, and mi- crohardness for NiTi synthesized by mechanical alloying for different milling durations. Increasing the milling duration led to the formation of a nanocrystalline NiTi intermetallic at a higher level. The formation of nanocrystalline materials was directed through cold fusion, fractur- ing, and the development of a steady state, which were influenced by the accumulation of strain energy. In the morphological study, uninter- rupted cold diffusion and fracturing were visualized using transmission electron microscopy. Particle size analysis revealed that the mean particle size was reduced to -93 μm after 20 h of milling. The mechanical strength was enhanced by the formation of a nanocrystalline in- termetallic phase at longer milling time, which was confirmed by the results of Vickers hardness analyses.展开更多
目的设计一种开放式记忆合金人工椎体,用于胸腰椎肿瘤、爆裂性骨折、侧弯及后凸畸形等脊柱疾患手术切除病变椎体后脊柱结构的重建,并对其进行生物力学分析。方法采用医用镍钛(NiTi)形状记忆合金加工制成开放式记忆合金人工椎体。选取正...目的设计一种开放式记忆合金人工椎体,用于胸腰椎肿瘤、爆裂性骨折、侧弯及后凸畸形等脊柱疾患手术切除病变椎体后脊柱结构的重建,并对其进行生物力学分析。方法采用医用镍钛(NiTi)形状记忆合金加工制成开放式记忆合金人工椎体。选取正常成年新鲜猪脊柱标本8个,取材范围T14～L5。将每个标本按以下操作依次制作4种模型并按此分组:完整椎体(A组);行T15、L1、L3、L4椎弓根钉固定(B组);人工椎体重建L2椎体,加T15、L1、L3、L4椎弓根钉固定(C组);钛网重建L2椎体,加T15、L1、L3、L4椎弓根钉固定(D组)。在MTS-858液压伺服材料试验机上依次完成各组模型T15～L1、L1～3、L3、4节段前屈、后伸、左右侧弯、左右旋转6个方向(加载力矩0～8N?m)三维运动范围(range of motion,ROM)的测试。结果与A组比较,B、C、D组各节段各方向的ROM均较小,比较差异有统计学意义(P<0.05)。C组各节段各方向的ROM与B组比较差异均无统计学意义(P>0.05)。与D组比较,C组T15～L1节段及L3、4节段各方向的ROM均较小,差异有统计学意义(P<0.05);L1～3节段各方向ROM差异无统计学意义(P>0.05)。结论 NiTi开放式记忆合金人工椎体结构设计合理,与钛网重建模型具有相近的术后即刻稳定性,在附加椎弓根钉固定的情况下能重建脊柱稳定。展开更多
文摘The formulation of nanocrystallinc NiTi shape memory alloys has potential effects in mechanical stimulation and medical im- plantology. The present work elucidates the effect of milling time on the product＇s structural characteristics, chemical composition, and mi- crohardness for NiTi synthesized by mechanical alloying for different milling durations. Increasing the milling duration led to the formation of a nanocrystalline NiTi intermetallic at a higher level. The formation of nanocrystalline materials was directed through cold fusion, fractur- ing, and the development of a steady state, which were influenced by the accumulation of strain energy. In the morphological study, uninter- rupted cold diffusion and fracturing were visualized using transmission electron microscopy. Particle size analysis revealed that the mean particle size was reduced to -93 μm after 20 h of milling. The mechanical strength was enhanced by the formation of a nanocrystalline in- termetallic phase at longer milling time, which was confirmed by the results of Vickers hardness analyses.
文摘目的设计一种开放式记忆合金人工椎体,用于胸腰椎肿瘤、爆裂性骨折、侧弯及后凸畸形等脊柱疾患手术切除病变椎体后脊柱结构的重建,并对其进行生物力学分析。方法采用医用镍钛(NiTi)形状记忆合金加工制成开放式记忆合金人工椎体。选取正常成年新鲜猪脊柱标本8个,取材范围T14～L5。将每个标本按以下操作依次制作4种模型并按此分组:完整椎体(A组);行T15、L1、L3、L4椎弓根钉固定(B组);人工椎体重建L2椎体,加T15、L1、L3、L4椎弓根钉固定(C组);钛网重建L2椎体,加T15、L1、L3、L4椎弓根钉固定(D组)。在MTS-858液压伺服材料试验机上依次完成各组模型T15～L1、L1～3、L3、4节段前屈、后伸、左右侧弯、左右旋转6个方向(加载力矩0～8N?m)三维运动范围(range of motion,ROM)的测试。结果与A组比较,B、C、D组各节段各方向的ROM均较小,比较差异有统计学意义(P<0.05)。C组各节段各方向的ROM与B组比较差异均无统计学意义(P>0.05)。与D组比较,C组T15～L1节段及L3、4节段各方向的ROM均较小,差异有统计学意义(P<0.05);L1～3节段各方向ROM差异无统计学意义(P>0.05)。结论 NiTi开放式记忆合金人工椎体结构设计合理,与钛网重建模型具有相近的术后即刻稳定性,在附加椎弓根钉固定的情况下能重建脊柱稳定。
