A Review on Biomedical Titanium Alloys: Recent Progress and Prospect

During the resorbable-polymer-boom of the 1970s and 1980s, polycaprolactone (PCL) was used in the biomaterials field and a number of drug-delivery devices. Its popularity was soon superseded by faster resorbable polymers which had fewer perceived disadvantages associated with long term degradation (up to 3-4 years) and intracellular resorption pathways; consequently, PCL was almost forgotten for most of two decades. Recently, a resurgence of interest has propelled PCL back into the biomaterials-arena. The superior rheological and viscoelastic properties over many of its aliphatic polyester counterparts renders PCL easy to manufacture and manipulate into a large range of implants and devices. Coupled with relatively inexpensive production routes and FDA approval, this provides a promising platform for the production of longer-term degradable implants which may be manipulated physically, chemically and biologically to possess tailorable degradation kinetics to suit a specific anatomical site. This review will discuss the application of PCL as a biomaterial over the last two decades focusing on the advantages which have propagated its return into the spotlight with a particular focus on medical devices, drug delivery and tissue engineering.

The return of a forgotten polymer : Polycaprolactone in the 21st century

Progress in additive manufacturing on new materials: A review

Research status of laser cladding on titanium and its alloys: A review

Promoting the columnar to equiaxed transition and grain refinement of titanium alloys during additive manufacturing

In this study, Ti-Al-xNb coatings were deposited on a Ti-6Al-4V alloy by laser surface alloying in order to investigate their oxidation resistance. A Ti-Al coating was fabricated for comparison. It was found that the Ti-Al and Ti-Al-xNb coatings were composed of TiAl and Ti3Al phases. Nb addition reduced the cracking tendency of the Ti-Al-xNb coatings. The Ti-Al and Ti-Al-xNb coatings exhibited good high-temperature oxidation resistance at 800 °C. In comparison, Ti-Al-xNb (x = 10, 20, 30 and 40) coatings had better high-temperature oxidation resistance and Ti-Al-40Nb coating had the best high-temperature oxidation resistance. The mechanism of Nb that improves the high-temperature oxidation resistance of Ti-Al-xNb coatings includes preventing the internal diffusion of oxygen, inhibiting the formation of TiO2, promoting the formation of Al2O3 and increasing the adhesion of the oxide scales.

Microstructure and high-temperature oxidation resistance of Ti-Al-Nb coatings on a Ti-6Al-4V alloy fabricated by laser surface alloying

Controlled sulfidation towards achieving core-shell 1D-NiMoO4 @ 2D-NiMoS4 architecture for high-performance asymmetric supercapacitor

Structure and in vitro bioactivity of ceramic coatings on magnesium alloys by microarc oxidation

In this study, Co-based laser cladding coatings reinforced by multiple phases were fabricated on titanium alloy. Co42 Co-based self-fluxing alloy, B4C, and CeO2 mixed powders were used as the precursor materials. The coatings were mainly composed of γ-Co/Ni, CoTi2, CoTi, NiTi, TiC, Cr7C3, TiB2, and TiB phases. A typical TiB2/Cr7C3/TiC composite structure was chosen. It was found that CeO2 did not influence the phase types of the coating significantly, but was effective in refining the microstructure and enhancing the microhardness and dry sliding wear resistance. Compared with the Ti-6Al-4V titanium alloy, the microhardness and wear resistance of the composite coatings were enhanced by 3.44–4.21 times and 14.26–16.87 times, respectively.

Fabrication of Co-Based Coatings on Titanium Alloy by Laser Cladding with CeO2 Addition

Ni-based superalloys with niobium (Nb) or/and yttrium (Y) were prepared by vacuum melting. The oxidation kinetics of these alloys was studied by thermogravimetry at 800 °C for 100 h in static air. Morphology of oxides was studied using SEM, and the composition was analyzed by X-ray diffraction. Energy-dispersive X-ray spectrometer was employed to examine the linear element distribution of the cross section of the oxidation films. Results showed that the oxidation kinetics all followed a parabolic law at different stages. The oxide films were mainly comprised of Cr2O3, NiCr2O4, Al2O3 and TiO2. All the oxide films exhibited layered structure owing to different oxidation stages. With the addition of Nb or Y, the high-temperature oxidation resistance of the superalloy was improved significantly and the surface morphology of the oxidation film was ameliorated. The comprehensive effect of Nb and Y was remarkable in improving the high-temperature oxidation resistance of Ni-based alloys. Copyright © 2014 John Wiley & Sons, Ltd.

Huijun Yu

Papers

Microstructure and high-temperature oxidation resistance of Ti-Al-Nb coatings on a Ti-6Al-4V alloy fabricated by laser surface alloying

Controlled sulfidation towards achieving core-shell 1D-NiMoO4 @ 2D-NiMoS4 architecture for high-performance asymmetric supercapacitor

Structure and in vitro bioactivity of ceramic coatings on magnesium alloys by microarc oxidation

Fabrication of Co-Based Coatings on Titanium Alloy by Laser Cladding with CeO2 Addition

High‐temperature oxidation behavior of Ni‐based superalloys with Nb and Y and the interface characteristics of oxidation scales