Wyniki wyszukiwania - BazTech

Ograniczanie wyników

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: TLP bonding

Sortuj według:

Ogranicz wyniki do:

The effect of post-bond solution treatment and double aging on the microstructural evolution and mechanical properties of TLP-bonded IN718 joint

Tarai U. K., Pal Sukhomay, Robi P. S.

Archives of Civil and Mechanical Engineering

2023

Vol. 23, no. 2

art. no. e110, 2023

The effect of post-bond heat treatment on precipitation of different strengthening phases in transient liquid phase (TLP) bonded IN718 joint is carried out in this work. TLP bonding of IN718 super-alloy was carried out using commercial BNi-2 amorphous interlayer. The bond microstructure of the IN718 joint was analyzed by field emission scanning electron microscope. The bond microstructure showed three distinct zones: viz., base material zone, where δ-phase was observed in the grain boundaries; diffusion-affected zone (DAZ) consisting of extensive diffusion-induced boride precipitates and isothermal solidification zone where a single-phase γ solid solution exists along with a small amount of silicides. The effect of post-bond heat treatment on the microstructure and precipitates formed at different zones was investigated in detail. The phase formed during post-bond heat treatment was analyzed by field emission transmission electron microscope and X-RD. The mechanical properties of as-bonded and post-bond heat treatment samples were also investigated. The results showed that a comparatively more homogeneous microstructure was achieved in the post-bond heat-treated samples. Post-bond heat treatment resulted in decrease in the volume fraction of borides at the DAZ, increase in volume fraction of hardening precipitates (γ’’ and γ’), and breaking up of grain boundary borides and increase in the DAZ size. An increased in γ’’ + γ’ precipitate volume was beneficial to the improvement of mechanical properties of the joint. Tensile strength of 1124 MPa with an elongation percentage of 10.5% was obtained after the post-bond heat treatment.

Transient Liquid Phase bonding of γTiAl using Al films and SPS method

Szastak K., Matsuura K., Kata D., Ohno M.

Journal of Achievements in Materials and Manufacturing Engineering

2014

Vol. 67, nr 1

5--13

Purpose: Investigation of joining γ-titanium aluminides using Al interlayers. Design/methodology/approach: : In order to achieve a proper joining of TiAl elements, a method known as Transient Liquid Phase (TLP) bonding was combined with Spark Plasma Sintering (SPS). All the experiments were performed under a uniaxial pressure of 7.4 MPa in a vacuum to prevent possible oxidation of liquid Al in the interlayer. The study analyzed the difference in microstructure of joints achieved with Al film thicknesses of 50, 100, 200 and 300 μm, as well as two different bonding temperatures of 900 and 1100°C. After bonding the samples were cross-sectioned, polished using 220-1200 mesh SiC paper, and 1/4 μm diamond dispersion, and analyzed using OM, SEM, EDS and EBSD, while Vickers hardness tests were performed to compare the hardness of the joint to that of the base material. Findings: The analysis of the microstructures revealed that a joint has been created between the two starting γTiAl elements. The bond consisted of TixAly phases, with some presence of Ti2AlC and TiC. The Vicker’s hardness tests reviled in some cases similar results to those of base material. Research limitations/implications: Presence of carbon rich phases within the joint, are the result of graphite mold and filling what react with molten Aluminum. This can be counteracted by replacing graphite with prefabricated TiAl powder after SHS. That however results in increasing the amount of phases such as Ti3Al, TiAl2 and TiAl3, different from the original γTiAl within the joint. An increase in bonding time and temperature could allow for faster homogenization in the joint, but would make the process more expensive and time-consuming. Practical implications: The process allows for creation of strong joints, showing signs of homogenization. Low temperature and short time makes it a possible candidate for joining γTiAl elements. Originality/value: The use of Al instead of commonly used Cu or Ni, allows minimalization of introduce impurities into the joint, while Al is still cheap and common and thus doesn’t increase the cost of the process.