Research Article Effect of Aluminium Tetrahydrate Nanofiller Addition on the Mechanical and Thermal Behaviour of Luffa Fibre-Based Polyester Composites under Cryogenic Environment G. Velmurugan , 1 V. Siva Shankar, 1 S. Kaliappan, 2 S. Socrates, 2 S. Sekar, 3 Pravin P. Patil, 4 S. Raja, 5 L. Natrayan , 6 and Ketema Bobe 7 1 Institute of Agricultural Engineering, Saveetha School of Engineering, SIMATS, 602 105, Chennai, Tamilnadu, India 2 Department of Mechanical Engineering, Velammal Institute of Technology, Chennai, 601204 Tamil Nadu, India 3 Department of Mechanical Engineering, Rajalakshmi Engineering College, Rajalakshmi Nagar, Thandalam, Chennai, 602 105 Tamil Nadu, India 4 Department of Mechanical Engineering, Graphic Era Deemed to Be University, Bell Road, Clement Town, 248002 Dehradun, Uttarakhand, India 5 School of Mechanical Engineering, Vellore Institute of Technology, Vellore, Tamil Nadu, India 6 Department of Mechanical Engineering, Saveetha School of Engineering, SIMATS, Chennai, Tamil Nadu 602105, India 7 Department of Mechanical Engineering, Ambo University, Ambo, Ethiopia Correspondence should be addressed to G. Velmurugan; velresearch032@gmail.com, L. Natrayan; natrayanmech007@gmail.com, and Ketema Bobe; ketema.bobe@ambou.edu.et Received 10 April 2022; Revised 12 May 2022; Accepted 24 May 2022; Published 11 June 2022 Academic Editor: R Lakshmipathy Copyright © 2022 G. Velmurugan et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. In recent times, research has shifted away from conventional materials and alloys and more towards nanocomposites to create lighter, more efficient materials for specific applications. The major goal of this research is to see how successful adding aluminium tetrahydride (ATH) filler to a luffa fibre/polyester-based hybrid composite is. The compression moulding process was used to create the nanocomposite. The following limitations were used to achieve the goals mentioned above: (i) weight percent of ATH, (ii) weight percent of luffa fibres, and (iii) cryogenic treatment hours. The mechanical properties of the materials, such as flexural, tensile, and impact, were examined. The scanning electron microscope observed the morphology pictures, revealing flaws such as interface behaviour, fibre pullouts, voids, and interior cracks. As a result, the current study found that adding nanofiller to a natural fibre composite can improve its mechanical properties, because it established a strong link between the matrix and its reinforcements, which would aid in the effective transmission of stress in the hybrid system. It also improved moisture resistance, which might be useful in construction and commercial industries. The composite with 1 wt.% of ATH, 24 wt.% of luffa fibres, and 30 minutes of cryogenic treatment showed better mechanical strength. Cryogenic treatment reduces compressive interface stresses, which helps maintain fibre and matrix in contact and improve adhesion, resulting in superior results. TGA analysis was used to confirm it. 1. Introduction Glass fibre-reinforced (GFR) composites currently come in a wide range of prices and mechanical properties. Shipbuilding and car manufacture, as well as turbine making, are all instances of industrial purposes. GFR composites, on the other hand, are made of nonrenewable resources and are known to use a significant amount of energy during manufacturing. Aside from that, GFR recycling is not easy [1, 2]. Environmen- tal concerns are growing in importance, prompting the development of more environmentally friendly composite materials. Natural fibres are frequently regarded as being more Hindawi Journal of Nanomaterials Volume 2022, Article ID 5970534, 10 pages https://doi.org/10.1155/2022/5970534