Mater Sci Eng C Mater Biol Appl. 2012 Aug 1;32(6):1480-5. doi: 10.1016/j.msec.2012.04.028. Epub 2012 Apr 24.
Porous metallic structures are attractive for biomedical implant applications as their open porosity simultaneously improves the degree of fixation and decreases the mismatch in stiffness between bone and implant, improving bonding and reducing stress-shielding effects respectively. NiTi alloys exhibit both the shape memory effect and pseudoelasticity, and are of particular interest, though they pose substantial problems in their processing. This is because the shape memory and pseudoelastic behaviours are exceptionally sensitive to the presence of oxygen, and other minor changes in alloy chemistry. Thus in processing careful control of composition and contamination is vital. In this communication, we investigate these issues in a novel technique for producing porous NiTi parts via transient liquid phase sintering following metal injection moulding (MIM) of elemental Ni and Ti powders, and report a new mechanism for pore formation in the powder processing of metallic materials from elemental powders.
多孔金属结构在生物医学植入物应用中很有吸引力，因为其多孔结构同时提高了固定程度，并降低了骨与植入物之间的刚度不匹配程度，分别提高了结合度并减少了应力屏蔽效应。NiTi 合金具有形状记忆效应和伪弹性，特别受到关注，尽管它们在加工方面存在很大的问题。这是因为形状记忆和伪弹性行为对氧的存在以及合金化学成分的其他微小变化非常敏感。因此，在加工过程中，对成分和污染的严格控制至关重要。在本通讯中，我们通过元素 Ni 和 Ti 粉末的金属注射成型（MIM）后进行瞬时液相烧结来生产多孔 NiTi 零件的新技术中研究了这些问题，并报告了一种从元素粉末加工金属材料的粉末中形成孔的新机制。
