Effect of Titanium Addition on the Structure, Microstructure, and Selected Mechanical Properties of As-Cast Zr-25Ta-xTi Alloys

Ti alloys are the most used metallic materials in the biomedical field due to their excellent biocompatibility associated with good corrosion resistance in body fluids and relatively low elastic modulus. However, the alloys used in the orthopedic area have an elastic modulus that is 2 to 4 times higher than that of human cortical bone. Searching for new alloys for biomedical applications and with low elastic modulus, zirconium gained prominence due to its attractive properties, especially its biocompatibility. The purpose of this paper is to present novel as-cast alloys of the Zr-25Ta-xTi system and analyze the influence of titanium on the structure, microstructure, microhardness, and elastic modulus of the alloys. The alloys were prepared using an arc-melting furnace. X-ray diffraction measurements and microscopy techniques were used to characterize the crystalline structure and microstructure. From structural and microstructural characterizations, it was observed that titanium acted as an α-stabilizing element since its increase in the precipitation of the orthorhombic α” phase, an intermediate phase from β to α phases, in the alloys. Regarding microhardness measurements, the alloys have higher hardness than pure zirconium due to solid solution hardening that detaches the Zr-25Ta alloy, which has a high hardness value of the precipitation of the ω phase. Among the studied alloys, the Zr-25Ta-25Ti alloy is highlighted, demonstrating the lowest result of modulus of elasticity, which is approximately 2 times higher than the human cortical bone, but many alloys used in the biomedical field, such as pure titanium, have elastic modulus values almost 3 times higher than that of human bone.

Effect of Titanium Addition on Cracks of Fe-Cr-C Coating by Reactive Plasma Cladding

Fe-Cr-C and Fe-Cr-C-Ti coatings were prepared by reactive plasma cladding in this paper. The crack morphology and fracture surface of the Fe-Cr-C coating were observed by SEM. The effect of titanium addition on the crack of Fe-Cr-C coating was analyzed. The results show that the coating cracks mainly consist of crack perpendicular to the fusion line, defect-induced crack and intergranular crack. The crack rate of Fe-Cr-C-Ti coating was obviously decreased after Titanium was added. When the titanium content is below 8 wt.%, with the increase of titanium content, the crack rate of Fe-Cr-C-Ti coating decreases obviously. When titanium content is between 8wt.% and 13wt.%, there are no cracks in the Fe-Cr-C-Ti coating. When the titanium content exceeds 13 wt.%, with the increase of titanium content, a small number of cracks begin to appear. The addition of titanium increases the toughness of the Fe-Cr-C-Ti coating and reduces the stress concentration.

Grain Size Evolution and Mechanical Properties of Nb, V–Nb, and Ti–Nb Boron Type S1100QL Steels

Titanium additions are often used for boron factor and primary austenite grain size control in boron high- and ultra-high-strength alloys. Due to the risk of formation of coarse TiN during solidification the addition of titanium is limited in respect to nitrogen. The risk of coarse nitrides working as non-metallic inclusions formed in the last solidification front can degrade fatigue properties and weldability of the final product. In the presented study three microalloying systems with minor additions were tested, two without any titanium addition, to evaluate grain size evolution and mechanical properties with pre-defined as-cast, hot forging, hot rolling, and off-line heat-treatment strategy to meet demands for S1100QL steel. Microstructure evolution from hot-forged to final martensitic microstructure was observed, continuous cooling transformation diagrams of non-deformed austenite were constructed for off-line heat treatment, and the mechanical properties of Nb and V–Nb were compared to Ti–Nb microalloying system with a limited titanium addition. Using the parameters in the laboratory environment all three micro-alloying systems can provide needed mechanical properties, especially the Ti–Nb system can be successfully replaced with V–Nb having the highest response in tensile properties and still obtaining satisfying toughness of 27 J at –40 °C using Charpy V-notch samples.

Effect of Titanium Modification on Microstructure and Impact Toughness of High-Boron Multi-Component Alloy

This work investigated the microstructure and mechanical property of high-boron multi-component alloy with Fe, B, C, Cr, Mo, Al, Si, V, Mn and different contents of Ti. The results indicate that the as-cast metallurgical microstructure of high-boron multi-component alloys consist of ferrite, pearlite and borocarbide. In an un-modified alloy, continuous reticular structure of borocarbide is observed. After titanium addition, the structure of borocarbide changes into a fine and isolated morphology. TiC is the existence form of titanium in the alloy, which acts as the heterogeneous nuclei for eutectic borocarbide. Moreover, impact toughness of the alloy is remarkably improved by titanium modification.

Effect of titanium content on the microstructure and wear behavior of Fe(13-x)TixB7 (x=0-5) hardfacing alloy

In this study, the effects of titanium addition on microstructure, hardness and wear rate of Fe(13-x)TixB7 (x = 0, 1, 2, 3 and 5) based hard surface alloy layers formed by gas tungsten arc (GTA) welding method were investigated. As a result of the microstructure studies and phase analysis, it was determined that the structures of the coating layers consisted of ?-Fe, ?Fe+Fe2B eutectic, ?-Fe+Fe2Ti eutectic and hard TiB2 phases. In the hard surface alloy layer, as the amount of titanium was increased, the TiB2 phase density formed in the system increased and it was observed that rod-like and long sharp-edged phases formed from the equiaxed structure. As a result of wear tests performed at different loads, it was determined that the addition of titanium reduces the wear rates in the coating layers. In addition, scanning electron microscopy (SEM) images of the worn surfaces showed that the wear mechanisms were adhesive and oxidative.

Enhancement of boron removal from metallurgical-grade silicon by titanium addition during slag refining

The effects of titanium addition (0 wt.%, 0.2 wt.%, and 0.5 wt.%) on the boron removal from metallurgical-grade silicon during slag refining have been studied. According to the findings, the addition of Ti improved the removal of 92.5 wt.% B with 0.5 wt.% Ti addition compared to 79.4 wt.% B removal without Ti addition. Furthermore, acid leaching reduced excess Ti to 27 ppmw.