Recent developments are presented on powder injection moulding of titanium from metal hydride powders and binders composed of polyethylene, paraffin wax and stearic acid. The feasibility of using this route to process fit for purpose, complex parts is assessed. Titanium hydride offers a low cost solution compared with pure titanium powders. Feedstocks for powder injection moulding were prepared in a sigma mixer. Tensile test specimens and demonstration parts were injection moulded. Solvent debinding in heptane was followed by thermal debinding and dehydrogenation under argon. Titanium parts were sintered at 1200°C under argon. Sintered parts exhibit a linear shrinkage of about 20%, good shape preservation and reproducibility. The yield strength (519 MPa), ultimate tensile strength (666 MPa), elongation to fracture (15%) and interstitial content measured by quantitative analysis meet the requirements for titanium grade 4.

Ti–Nb alloys are attractive as biomaterials because of their excellent combination of low elastic modulus, high strength, corrosion resistance and enhanced biocompatibility. The effect of a post-sintering quenching treatment on the microstructure and mechanical properties of powder injection moulded Ti–17Nb has been investigated. Tensile test specimens were produced using a feedstock based on blended elemental powders, some of which were solution-treated in the β phase field and water quenched. Both as-sintered and quenched alloys had densities 95·5% of theoretical. The as-sintered material showed an α−β structure, whereas after quenching a fully martensitic α″ structure was obtained. The modulus of elasticity of the water-quenched alloy (∼45 GPa) was about 40% lower than that of the as-sintered alloy (∼76 GPa).

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Abstract. TiNi shape-memory properties are successfully used today for the fabrication of various technical devices. The limited machinability and high cost of TiNi encourage the use of near-net shape production techniques such as metal injection moulding. In this work TiNi alloys tensile test specimens are produced by metal injection moulding from pre-alloyed powders. A binder based on a mixture of polyethylene, paraffin wax and stearic acid is used. Parts with a density of about 96.6% of theoretical density are obtained. Scanning electron microscopy coupled with EDX measurements reveals a microstructure consisting of a TiNi matrix with small Ti 4 Ni 2 O x and TiC inclusions. DSC and X-ray diffraction observations indicate the presence of additional Ni 4 Ti 3 precipitates. The parts exhibit full superelasticity at room temperature even for strains of up to 4%, without the need for additional thermal post-treatments. Ultimate tensile strengths up to 980 MPa are obtained.

Aliphatic polyesters, such as polylactic acid (PLA), polyglycolic acid (PGA), and their copolymer polylactic-co-glycolic acid (PLGA) have become an established choice in the biomedical field in a wide range of applications, from nanoparticles for local drug delivery to bone fixation screws, and, hence, in a huge spectrum of uses in different medical devices currently available on the market worldwide. The reason for their popularity lies in their combination of interesting peculiarities: in situ degradation, intrinsic biocompatibility (degradation products are recognized and metabolized), processability with standard industrial technologies, and tailorable properties. The knowledge of the degradation rate is an essential requirement for optimal device design when, e.g., fast adsorption time is required, or mechanical properties must be assured over a given time span. In this regard, experimental studies can be time- and money-consuming, due to the time scales (weeks–months) involved in the hydrolysis process. This work aims at providing to both industry and academia robust guidelines for optimal material choice through a systematic experimental and computational analysis of most commonly used PLGA formulations (selected from commercially available products), evaluating the degradation kinetics and its impact on polymer properties.