Editors: | F. Kongoli, M. Delferro, P. S. Halasyamani, M. A. Alario-Franco, F. Marquis, A. Tressaud, H. Kageyama |
Publisher: | Flogen Star OUTREACH |
Publication Year: | 2023 |
Pages: | 144 pages |
ISBN: | 978-1-989820-86-5 (CD) |
ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
Titanium is not rare, being the ninth most abundant chemical element in the earth's crust, behind metals such as aluminum, iron and magnesium.[1] Nickel and titanium alloys (Ni-Ti) are part of a group of metallic alloys whose main feature is the shape memory effect (EMF), known as shape memory alloys (SLM), or smart alloys. This alloy was characterized by having excellent electrical and mechanical properties, high resistance to corrosion and fatigue, with values equal to or greater than those of stainless steel ABNT 316L and titanium alloy ASTM F 136. [2] The intermetallics formed are very difficult. to be removed by subsequent heat treatments, being thermodynamically more stable than NiTi. The emergence of these intermediate phases is related to the manufacturing process of the alloy and the subsequent thermal or thermomechanical treatments. [3] Biocompatibility is understood as the affinity that must exist between a certain material and the biological environment in which it needs to remain. The material implanted in the body may or may not produce reactions. [4]
Compared to conventional metallurgy, the Powder Metallurgy technique has become competitive both for technological and economic reasons: in the production of large quantities of parts, in complex shapes or with base material with a high melting point. It is a technique in constant evolution, with the development of new alloys.[5] After obtaining the metallic powders, the compaction step takes place, called Cold Pressing, which occurs at room temperature. In this process, the powder is placed in die cavities mounted on compression presses, being compressed to determined pressures, according to the type of powder used and the final characteristics desired in the sintered products.[6]
Sintering is a thermal treatment process in which particles are united, on an atomic scale, by means of mass transport mechanisms. The union of these particles consumes a good portion of the surface energy, causing an increase in the mechanical strength of the compact and a state of lower energy in the system.[7]