From the time when Per-Ingvar Brånemark discovered oseointegration properties of titanium in 1952 a large-scale studies on the issue of usability this metal in surgery were started. Thanks to the parallel research conducted on independent centers managed to get a number of metal alloys which were implanted into the human body in the form of implants. Among the alloys produced appeared alloy of aluminum and vanadium Ti6Al4V. The mechanical properties, high biocompatibility, low density and for this relatively low-cost, caused that the alloy began to be used as a material for biomedical applications. In the present article analyzed the possibility of modifying the properties of the alloy, by choosing another method of producing – method of injection casting with suction. A comparative analysis of the input material - the alloy commercially produced in the form of a rod of the same material melted by injection under vacuum and in air were carried out. The studies results indicate that using method of injection casting with suction to produce the final item influence on significant improvement in mechanical properties as a result of fragmentation of the grains at the element surface. The mechanical properties play a key role in a tissue-implant-bone system.

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The material subject to investigation was two commercial alloys of cobalt CoCrW (No. 27 and 28) used in prosthodontics. The scope of research included performing an analysis of microstructure and functional properties (microhardness, wear resistance and corrosion resistance), as well as dilatometric tests. The examined alloys were characterized by diverse properties, which was considerably influenced by the morphology of precipitates in these materials. Alloy No. 27 has a higher corrosion resistance, whereas alloy No. 28 shows higher microhardness, better wear resistance and higher coefficient of linear expansion. Lower value of the expansion coefficient indicates less probability of initiation of a crack in the facing ceramic material.

The paper attempts to improve the properties of Ti6Al4V titanium alloy by the using of the injection casting method with rapid cooling. The comparison of the structure and properties of the Ti6Al4V titanium alloy formed by two methods: the injection casting under pressure in two variants under air and vacuum with using a rapid cooling and purchased commercially were carried out. Design/methodology/approach: Samples were produced by two methods: unconventional casting by injection under pressure of gas or vacuum to copper mold with rapid cooling, and a traditional method for the production of titanium alloys in a form of a rod. To achieve the pursued objective the following tests were performed: microstructural observations-light microscope and SEM, corrosion resistance tests, microhardness tests-Vickers method. Findings: Microstructural observations showed that the Ti6Al4V titanium alloy produced by injection casting method under pressure with rapid cooling is able to produce extremely fine-grained layer and ductile core. That distribution of structures significantly affect on the improvement of a number of properties compared to commercially produced material. Moreover, during process increased corrosion resistance was observed. Those properties have a significant impact on the possibility of using that type of a production method and material in many areas of materials science related with medicine. Research limitations/implications: In the framework of the studies, tests using living tissues, which would allow to determine whether the produced material is biocompatible and does not cause inflammation, have not been conducted. Practical implications: The application of injection casting carries some complications, which mainly relate to quartz capillary where ingot is melted. Titanium as a reactive element strongly absorbs silicon out of the capillary causing changes in the chemical composition in the surface layer of the final element. Further studies will be attempted to use a different type of material wherein the alloy will be melted. Originality/value: The paper presents the improvement of the properties of materials produced under pressure by casting injection, compared to the same material produced by a commercial method.

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