Material Processing
Ajay Kumar Baranwal; D P Mondal; Rajeev Kumar
Abstract
Lightweight Ni-Ti alloy foam has received immense attention as a promising material for sensors, actuators, dampers, biomedical implants, and energy absorption applications due to their outstanding properties including low density, high surface area, corrosion resistance and excellent mechanical strength. ...
Read More
Lightweight Ni-Ti alloy foam has received immense attention as a promising material for sensors, actuators, dampers, biomedical implants, and energy absorption applications due to their outstanding properties including low density, high surface area, corrosion resistance and excellent mechanical strength. In the present study, we developed Ni (50)-Ti (50) alloy foams with varying porosities using NaCl as a space holder. The cold compacted mixture of NiTi alloy powder, NaCl granules, and 2 wt% polyvinyl alcohol (PVA) solutions are mixed uniformly in a globe box for 8 hrs. Sintering is carried out in two stages: firstly, at 900 oC for 2 hrs and then at 1100 oC for two hrs. During sintering, NaCl gets melted and removed from the foams. The Ni-Ti alloy foams exhibit an excellent compressive strength of 48 MPa at a relative density (ρrd) of 0.45. It also provides higher plateau stress, greater strain hardening effect, and larger strain recovery. Thus, the lightweight high strength Ni-Ti alloy foam is a promising material for bone implants and energy absorption applications.
Mohammed Menhal Shbeh; Russell Goodall
Abstract
Titanium foams are advanced materials with macroporous structure that have a great potential in a variety of areas such as biomedical and functional applications. They are characterized by their reduced density and stiffness, with high permeability and excellent biocompatibility. One production technique ...
Read More
Titanium foams are advanced materials with macroporous structure that have a great potential in a variety of areas such as biomedical and functional applications. They are characterized by their reduced density and stiffness, with high permeability and excellent biocompatibility. One production technique for Ti foams with promising results is Metal Injection Moulding (MIM). So far most of the porous titanium produced by this technique has a very basic design with low percentage of porosity, thus limiting its potential in the biomedical industry, among others. In this study, the use of MIM in combination with a space holder to produce single and multi-layered porous Ti with high volume percentage of porosity will be explored. The results show that it is possible to produce Ti foam with a total volume percentage of porosity of 61 % through MIM technology. In addition, it is also feasible to combine different porous layers resulting in multi-layered porous titanium parts with gradient porosity that could have a huge potential in a wide range of applications, especially for biomedical implants, where these pores can promote bone ingrowth as well as reduce stiffness to match that of the natural bone, thus alleviating the stress shielding problem.
)