Akshay Pathania
@iitjammu.ac.in
Research Scholar
IIT Jammu
EDUCATION
B.Tech in Mechanical Engineering
M.E. in CAD/CAM
P.hD in Metal Additive Manufacturing
RESEARCH INTERESTS
Metal additive manufacturing, Refurbishment through laser powder bed fusion, Experimental tribology, Fatigue, fracture
Scopus Publications
Scopus Publications
Rukmangad S. Barad, Akshay Pathania, B. K. Nagesh, and S. Anand Kumar
Springer Nature Singapore
Akshay Pathania, Anand Kumar Subramaniyan, and Nagesha Bommanahalli Kenchappa
ASTM International
Amit Kumar Tigga, Subramaniyan Anand Kumar, Nagesha Bommanahalli Kenchappa, and Akshay Pathania
Springer Science and Business Media LLC
Akshay Pathania, S Anand Kumar, and BK Nagesha
SAGE Publications
This paper investigates the tensile behaviour of Laser powder bed fusion (LPBF) processed Ti6Al4 V samples under three build orientations. The effect of microstructural changes from the post-heat treatments (PHTs – 850 °C, 950 °C 1050 °C) was assessed. The microstructural characterization was performed using optical microscopy, X-ray diffraction, and SEM techniques. The tensile tests were performed using a uniaxial universal testing machine (UTM). The fractal dimension analysis was performed on the fractured surfaces using ImageJ software integrated with an open-source MultiFrac plug-in. The PHT at a higher temperature (i.e., 1050 °C) induces a higher amount of β phase than the other PHTs. The PHT performed at 1050 °C exhibited α-Widmanstatten microstructure consisting of elongated β and a small amount of α. The PHT induces an isotropic behaviour in the LPBF-processed samples. However, the ductility of specimens subjected to PHT at 1050 °C showed ∼ 67%, 40%, and 177% improvement under horizontal (0°), inclined (45°), and vertical (90°) orientations than as-printed samples. Further fractal dimension analysis corroborates well with the ductility values of PHT samples. Therefore, the combination of fractography analysis and fractal dimension approach can be a promising methodology towards fractured surface characterization of additively manufactured metal parts.
Akshay Pathania, Anand Kumar Subramaniyan, and Nagesha Bommanahalli Kenchappa
SAGE Publications
The present work exploits the customized heat treatment, and laser powder bed fusion process to build direction effects on the densification behaviour and microstructural development in Ti6Al4V alloy. Optical microscopy evaluates the porosity and microstructure in different conditions. Further, the porosities are classified as inter-micropores (size < 10 µm) and super-micropores (size > 10 µm). Classification and quantifications of the porosities of laser powder bed fusion processed Ti6Al4V alloy under both directions due to customized heat treatment. The effect of customized heat treatment, the corresponding pore self-healing mechanism, and microstructure refinement on laser powder bed fusion-processed Ti6Al4V alloy were discussed. Moreover, the X-ray diffraction technique was used to analyse the different phases during laser powder bed fusion and customized heat treatment. The elevated customized heat treatment helps to reduce the overall porosity by two times that of as-printed samples due to the sintering self-healing phenomenon. Interestingly, the super micropores observed in as-printed samples are reduced via customized heat treatment ∼ 44% in a horizontal direction and ∼ 46% in a vertical direction, respectively, which is favourable for enhancing mechanical properties. This is because reducing these micropores leads to improved ductility. The ductility of the customized heat treatment executed sample was ∼ 68% in a horizontal orientation and ∼180% in a vertical orientation. The isotropic index for ductility in as-printed Ti6Al4V in the horizontal and vertical directions is 0.61. In contrast, it is 0.97 for customized heat treatment in both orientations showing high isotropy for customized heat treatment samples compared to as-printed samples. This study reveals that the customized heat treatment technique can be beneficial in introducing isotropic microstructure and densifying the distinctive laser powder bed fusion components.
Akshay Pathania, S Anand Kumar, and BK Nagesha
SAGE Publications
The present study investigated the influence of interface shear strength on the support removal effort without deviating the dimensional accuracy of laser powder bed fusion processed gear-type parts. The finite element method simulations were carried out to evaluate the effect of different process parameters of support structures on the distortion of laser powder bed fusion processed parts. Additionally, the dimensional accuracy of manufactured parts was assessed using a non-contact three-dimensional white light scanning technique. Support structures are the inevitable features in the laser powder bed fusion process. A simple in-house technique is adopted to evaluate the interface shear strength of support removal using a mechanical torque wrench. The support structures were fabricated with four different laser power and scanning speed. The results showed that all the laser powder bed fusion parts had insignificant dimensional deviation compared to the computer-aided design model despite changing the process parameters (laser power and scanning speed). However, the results indicated that ∼60% interface shear strength could be reduced with optimized process parameters which are favourable for easy part removal after printing.
Akshay Pathania, Anand Kumar S., Nagesha B.K., and Sanjay Barad
SAGE Publications
This article investigates the damping behaviour of laser powder bed fusion-processed Ti6Al4V thin plate samples and thin rotor blades. The effect of microstructural changes owing to the post heat treatments (PHTs – 850 °C, 950 °C and 1050 °C) on damping behaviour was assessed. The microstructural characterisation was performed using optical microscopy, X-ray diffraction and scanning electron microscope techniques. The impact hammer test was performed on thin plate samples and rotor blades to characterise damping behaviour. The microstructure of the thin plate samples subjected to PHT conditions varied in grain structure and morphology compared to the as-printed ones. Further, PHT at a higher temperature (i.e. 1050 °C) induces a higher amount of β phase than the other PHT temperatures. The PHT performed at 1050 °C exhibited α- Widmanstätten microstructure consisting of elongated β and a small amount of α. Moreover, the frequency response function plots revealed broader peaks for thin plate samples and the rotor blade than others. The PHT was favourable in enhancing the α lath thickness and β volume fraction, increasing the damping ratio. The results showed that PHT performed at 1050 °C improves the overall damping of ∼348% and ∼140% of rotor blade and thin plate samples, respectively. The amplitude decay for the rotor blade subjected to PHT at 1050 °C was ∼66% shorter than the as-printed one due to high β phase content relieving the energy resulting in a high damping ratio.
Akshay Pathania, Anand Kumar Subramaniyan, and B. K. Nagesha
Springer Science and Business Media LLC
B. K. Nagesha, S. Anand Kumar, S. Rajeswari, Sanjay Barad, and Akshay Pathania
Springer Science and Business Media LLC
S. Anand Kumar, Akshay Pathania, Abhishek Shrivastava, V. Rajkumar, and Prasad Raghupatruni
Wiley
B. K. Nagesha, S. Anand Kumar, S. Rajeswari, Sanjay Barad, and Akshay Pathania
Springer Science and Business Media LLC
Anand Kumar Subramaniyan, Sudarshan Reddy Anigani, Snehith Mathias, Akshay Pathania, Prasad Raghupatruni, and Shubhendra S Yadav
SAGE Publications
The post-heat treatment of direct metal laser sintered parts is expected to have superior mechanical properties. Therefore, the purpose of the present study is to investigate the post-heat treatment effect on the microstructure, mechanical and wear properties of direct metal laser sintering processed maraging steel. Hence, a systematic methodology for microstructural characterization, mechanical properties, and tribological performance evaluation was performed. The microstructural examinations were performed using optical and scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction technique. The micro-hardness and tensile properties were determined. The unidirectional sliding wear test was performed using a pin on disc wear testing machine for three different sliding velocities (0.8, 1.2, and 1.6 m/s) and three different normal loads (5, 10, and 15 N). The present study’s findings establish that the post-heat treatment techniques significantly altered the microstructural morphology and features. The results showed that the heat-treated sample had finer and non-continuous microstructure and more complex intermetallic precipitate phases, leading to higher hardness (∼64%) and higher tensile strength properties (70–80%) compared to the as-printed sample. The unidirectional sliding wear test results showed that the sliding velocity significantly affected frictional and wear characteristics of direct metal laser sintering processed maraging steel. The wear resistance of the heat-treated sample was three times higher than the as-printed sample, particularly at higher sliding velocities. In addition, the lower coefficient of friction values (∼24%) was observed for heat-treated sample compared to as-printed sample at higher sliding velocities. The post-heat treatment aids as an effective method to enhance mechanical properties of direct metal laser sintered parts and qualify them for tribological applications. The results endorse the suitability of the heat-treated direct metal laser sintered maraging steel in practical tool and die applications involving extreme tribological operating conditions such as higher sliding velocities and contact stresses.
Akshay Pathania, S. Anand Kumar, B.K. Nagesha, Sanjay Barad, and T.N. Suresh
Elsevier BV
BK. Nagesha, S. Anand Kumar, K. Vinodh, Akshay Pathania, and Sanjay Barad
Materials Today: Proceedings Elsevier BV
Abstract In the present study, selective laser melting (SLM) is used to fabricate the Inconel 718 high-pressure nozzle guide vane (HPNGV), an aero-engine part. Inconel 718 is widely used in aero-engine components due to its inherent characteristics at elevated temperature. The aim of the study is to investigate the residual stresses developed on the HPNGV part with and after removal of the base plate in the SLM process. The residual stresses were determined experimentally using X-ray diffraction technique. The maximum residual stress at location 4 was found around 700 MPa and A thermo-mechanical finite element model (FEM) was developed for SLM processed Inconel HPNGV using ANSYS software. SLM processed HPNGV part exhibited a higher magnitude of residual stresses after base plate removal. It is found that there is an increase of residual stress (about 16%) at location 4 and an increase of residual stress (about 27%) at location 2 after removal of base plate from the component. The experimental results of the samples were comparable with FEM simulation results.
Akshay Pathania, Satnam Singh, Dheeraj Gupta, and Vivek Jain
Elsevier BV