Search results

This study aims to investigate the production and abrasive wear rate of functionally graded TiB₂/Al composites. TiB₂ particles have been spontaneously formed in liquid matrix using in situ technique. The properties of composites such as hardness, abrasive wear rate and microstructure have been examined.

In situ TiB₂ reinforcement phase was synthesized by using a liquid Al–Ti–B system. A semi-solid composite (Al_(l)-TiB_2(s)) prepared at 900°C was solidified under a centrifugal force to both grade functionally and give the final shape to materials. Abrasive wear test of materials was conducted using the pin-on-disk method at room temperature. The wear tests were carried out with two different loads of 1 Newton (N) and 2 N, a sliding velocity of 3.5 m s⁻¹ and a sliding distance of 75 m.

This research provided the following findings; TiB₂ particles can be successfully synthesized with in situ reaction technique in molten aluminum. It was determined that abrasive wear rate increases with increasing load and decreases with increasing TiB₂ reinforcement content within matrix.

In previous studies, there have been many trials on the in situ production of TiB₂-reinforced aluminum matrix composites. However, there are few studies on production of in situ TiB₂-reinforced aluminum matrix functionally graded materials. At the same time, there is no study that the properties of composite, such as hardness and abrasive wear rate, are examined together according to centrifugal force.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-12-2019-0538/

Gamma titanium aluminide is a material essential for meeting military and civil engine performance targets in the future and potentially it could be used throughout the engine from compressor to combustor to turbine. The current alloy being used within Rolls‐Royce is the established Ti‐45‐2‐2‐XD. This is competing for lower temperature applications such as stators and structural components which take advantage of the lower costs arising from the casting route. Rigorous design criteria are required to compensate for the risks in using these relatively new materials in components and this requires investigation into the effects of manufactured surface conditions, of microstructures local to load bearing regions and of compositional variations. For the future, Rolls‐Royce has patented a next generation gamma titanium resulting from alloy development programmes undertaken by the University of Birmingham. The aim is to optimise castability with strength and creep resistance and their potential for commercial use within the aero‐engine is discussed.

This study aims to explore the machinability of ZrB₂ using electrical discharge machining (EDM) with different tool materials.

The workpiece for this study was fabricated through powder metallurgy compaction method. The disc is machined using diamond load grinding to have parallel surfaces, then, 2 mm diameter holes are machined on the disc using EDM spark erosion machine with different tool materials (graphite, aluminium, tantalum, niobium, copper, brass, silver, tungsten and titanium). Roundness, geometry of hole, and diameter of the hole at different diametric planes, surface roughness (SR), material removal rate (MRR), tool wear rate (TWR), taper angle and recast layer (RCL) thickness are measured. The photographic analysis of tools, holes in the top view, bottom view and sectional view. SEM analysis was conducted to study the recast layer. Desirability function analysis was employed to rate the performances of tools.

A new theory is developed which relates recast layer thickness with melting point and thermal conductivity of the tool materials. Machining of ZrB₂ by EDM is feasible; graphite is identified as the best tool. Recast layer thickness of the machined surfaces are indirectly proportional to the product of melting point and thermal conductivity of tool. Ablation behaviour of ceramic workpiece lead additional material losses in the tool.

Extremely high strength and hardness of ZrB₂ due to the coexistence of strong covalent and metallic bond make mechanical machining very difficult or even impossible. No machinability studies were conducted previously on ZrB₂ using EDM; this work reveals machinability study of ZrB₂ with different tool materials.

Ion Deposition Ltd is a new company established in Corby, Northamptonshire, as part of the SATRA Group of companies which specialises in international operations in the metals business. IDL has been set up as a specialist coating facility — with the support of the Department of Trade and Industry — initially offering ion vapour deposition of aluminium to, in particular, the Aerospace Industry. Significant investment has been made in equipment and facilities, including the latest state‐of‐art ivadizer from McDonnell Douglas. The vacuum chamber is capable of accepting a component 5ft by 10ft, yet has a barrel coating insert for the processing of large volumes of small parts like rivets and fasteners. The coater is also fitted with the capability of the first cryogenic pumping system, which achieves lower vacuums quickly and efficiently. The IDL plant has been in full operation for seven months, and has already established a firm Aerospace orientated customer base both in the U.K. and mainland Europe. Future plans include the expansion of the Corby facility to include other highly specialised coating services to meet the needs of ‘high tech’ industries in the 1990s'.

Aerospace field is demanding a material with superior strength and high resistance against wear, tear and corrosion. The current study aimed to develop a new material with high performance to be applicable in aerospace field

A metal matrix composite AA8090-WC-ZrC was fabricated using stir casting method and its tribological behavior was investigated. Totally, five composites viz. AA/Z, AA/W, AA/WZ (1:3), AA/WZ (1:1) & AA/WZ (3:1) were prepared. Micro hardness, tensile and wear study were performed on the fabricated composites and the results were compared with AA8090 alloy

Vickers hardness test resulted that the AA/W composite showed the higher hardness value of 160 HB compared to other materials due to the reinforcing effect of WC particles with high hardness. Tensile test reported that the AA/W composite displayed the maximum tensile strength of 502 MPa owing to the creation of more dislocation density. Further, wear study showed that the AA/W composite exhibited the least wear rate of 0.0011 mm3/m because of the more resisting force offered by the WC particles. Furthermore, the AA/W composite showed the slightest mass loss of 0.0028 g and lower COF value of 0.31 due to the hinder effect of WC particle to the movement of atoms in AA8090 alloy

This work is original in the field of aerospace engineering and materials science which deals with the fabrication of AA8090 alloy with the reinforcement particles such as tungsten carbide and zirconium carbide. The impact of the combination of hybrid particles and their volume fractions on the tribological properties has been investigated in this work. This work would provide new scientific information to society.