This study introduces powder interlayer bonding (PIB) as a novel joining technique, for the high integrity repair of components, fashioned from two titanium alloys commonly employed in the aerospace industry. The PIB technique in this study utilised a metallic powder interlayer between the two faying surfaces. Heating was provided via induction to create a bond in an inert atmosphere. The PIB technique proved capable of producing high integrity bonds in both Ti-6Al-4V and Ti-6Al-2Sn-4Zr-6Mo. A reduction of less than 10% in strength is seen for bonds created with both alloys. The deficit seen in ductility for the alloys was deemed acceptable for the industrial applications considered.

Powder interlayer bonding (PIB) is a joining technique originally developed to enable high-integrity repairs of aerospace components. The technique has previously been employed for the joining of titanium and nickel alloys utilised in the aerospace industry. This study expands on the application of the novel joining technique known as powder interlayer bonding (PIB), to the bonding of γ titanium aluminide (TiAl) material. PIB has been used to facilitate high-integrity joints in gamma titanium aluminides (TiAl), where full densification of the joint was achieved. The PIB technique described here used a metallic powder interlayer between the two faying surfaces of γ TiAl specimens. Bonds were formed in an inert atmosphere under induction heating. The PIB technique proved capable of producing high-integrity bonds in terms of microstructural evaluation, with very limited porosity retained after the bonding cycle. A brittle Ti₂Al phase can be produced with heavily oxidised powder which is susceptible to cracking and will negatively affect mechanical properties.

The low-cycle fatigue behavior of three titanium alloys (including two wrought alloys that are commercially available and one under development via a powder sintering technique) is described in order to assess the relative capabilities of a fourth, novel proprietary alloy, designated as RR11. Despite relatively increased levels of beta stabilization, each alloy remains within the general alpha–beta microstructural category and could be considered as an engineering alternative to the well-established Ti-6Al-4V. The relationships between fatigue behavior, microstructure, grain morphology, micro-texture, and alloy chemistry are explored. Emphasis is placed upon the potential cold dwell fatigue sensitivity of the four alternative alloys, which is particularly pertinent since it was recognized that Ti-6Al-4V can suffer from cold dwell-related behavior subject to selected thermo-mechanical processing.

Powder interlayer bonding (PIB) is a novel joining technique. The technique has been developed to facilitate high integrity repairs of aerospace components, manufactured from titanium alloys commonly employed in the aerospace industry. The PIB technique utilises an interlayer between the two faying surfaces. In this study heating was supplied via induction, enabling a bond to be created in an inert atmosphere, shielding the fusion zone from oxidation during bonding. The PIB technique proved capable of producing high integrity bonds in additive manufactured Ti-6Al-4V, where approximately 85% of the strength of the alloy is retained after bonding. Advantages of this technique over more established joining methods such as tungsten inert gas (TIG) welding and plasma arc (PA) welding include a narrow fusion zone and localised heating. It is believed that PIB can compete against these more mature techniques, providing a technique suitable for joining a range of alloys found in the aerospace industry.

Four alpha-beta titanium alloys, containing increased beta stabilising elements when compared to the well established Ti-6Al-4V, were previously characterised for their low cycle fatigue behaviour and resistance to cold dwell sensitivity. The same four alloys are now assessed for high cycle fatigue performance, employing plain cylindrical and notched specimen geometries. Fatigue strength under load-controlled cycling was measured under two contrasting mean stress conditions, a fully reversed R = −1 waveform and a positive mean stress waveform of R = 0.3. The role of microstructure and micro-texture are considered to explain the relative high cycle fatigue behaviour of each alloy and in particular the mechanisms responsible for fatigue crack initiation. The data are subsequently employed to construct “safe stress” range-mean diagrams.

Powder interlayer bonding (PIB) is a novel joining technique. The technique has been developed to facilitate high integrity repairs of aerospace components, manufactured from titanium alloys commonly employed in the aerospace industry. The PIB technique utilises an interlayer between the two faying surfaces. In this study heating was supplied via induction, enabling a bond to be created in an inert atmosphere, shielding the fusion zone from oxidation during bonding. The PIB technique proved capable of producing high integrity bonds in additive manufactured Ti-6Al-4V, where approximately 85% of the strength of the alloy is retained after bonding. Advantages of this technique over more established joining methods such as tungsten inert gas (TIG) welding and plasma arc (PA) welding include a narrow fusion zone and localised heating. It is believed that PIB can compete against these more mature techniques, providing a technique suitable for joining a range of alloys found in the aerospace industry.