Performance characterization of Bi 2 O 3 /Al nanoenergetics blasted micro-forming system Vinay Kumar Patel a, 1 , Rishi Kant b, 1 , Anu choudhary a , Madhusudan Painuly a , Shantanu Bhattacharya b, * a Department of Mechanical Engineering, Govind Ballabh Pant Institute of Engineering & Technology Pauri-Garhwal, 246194, Uttarakhand, India b Department of Mechanical Engineering, Indian Institute of Technology Kanpur, 208016, Uttar Pradesh, India article info Article history: Received 13 March 2018 Received in revised form 11 July 2018 Accepted 17 July 2018 Available online xxx Keywords: Microforming Aluminum Foil Bi 2 O 3 Nanoenergetic Tunability Process parameters abstract This paper reports a novel micro-blast driven manufacturing process for micro-forming of Aluminum foils. The micro-blast is realized by using a nanoenergetic material system comprising of Bi 2 O 3 micro- rods and aluminum particles. There is an enhanced need of forming of thin aluminum foil structures in small regions from point of view of drug packaging etc. The process developed caters to this need by using a single shot forming process using a micro-blast source. The micro-blast that is generated from an energetic composite system is made highly tunable by modulating the peak pressure generated through the blasting process and their impact in micro-forming of thin aluminum foils is observed through parametric studies. The engineering challenge involved in these experiments is to tune the blast pressure properties in order to address the forming of thin metal sheets with limiting boundary values as defined by the failure criteria. A variety of characterization techniques related to a thorough analysis of the synthesized material viz. X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) etc. are used to tune the functional properties like gauge blast pressure etc. of material system. We have found a material system that can generate a maximum peak pressure of 73.8 MPa with pressurization rate of 2460 GPa s 1 and that is able to accomplish micro-forming on thin metal foils (around 0.3 mm thickness). Experi- mental investigations demonstrate that tunabilty aspect of the energetic composites when exercised can enable variant processes such as embossing, coining, drilling etc. which may be of significant utility to drug packaging industries. A proper mathematical modeling of the forming process and critical process parameters therein have also been detailed. © 2018 Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/). 1. Introduction In recent years, the nano-energetic materials have emerged as advanced functional materials with properties such as ultra-fast energy release and excellent pressure-time characteristics result- ing in pulse power which can be deployed in many civilian and defence applications [3]. Nanoenergetic materials present a new class of meta-stable intermolecular composites which comprise of a nanoscale metal fuel (mostly aluminum nanoparticles) and transition metal oxides like CuO [1], Bi 2 O 3 [2,3], MoO 3 [4], Fe 2 O 3 [5], I 2 O 5 [6], Co 3 O 4 [7] etc. These materials produce a rapid releaseof heat and pressure by self-propagating combustion reaction. The density of the released energy and the overall combustion kinetics of such systems can be tailor made by altering the chemical composition, size and scale (microscale/nanoscale/atomic scale), morphology and the level of assembly among these composites. The fuel and oxidizer particles in the nano-scale possess enhanced surface area and reduced inter-diffusion distance which leads to elevated rate of exothermic reactions, higher ignition sensitivity and enhanced energy release rate with minimum heat dissipation [8,9]. The impulse caused by these energetic materials finds useful applications in microthrusters [10], safe arm devices [11], and drug/ gene delivery micro-devices [12]. In this article, we have investi- gated the impulse of energetic material systems for metal (aluminum foil in our case) forming applications. Such micro- formed products find wide ranging applications in many areas like packaging of pills in pharmaceutical products, small * Corresponding author. E-mail address: bhattacs@iitk.ac.in (S. Bhattacharya). Peer review under responsibility of China Ordnance Society 1 These authors contributed equally to this work. Contents lists available at ScienceDirect Defence Technology journal homepage: www.elsevier.com/locate/dt https://doi.org/10.1016/j.dt.2018.07.005 2214-9147/© 2018 Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Defence Technology xxx (2018) 1e8 Please cite this article in press as: Patel VK, et al., Performance characterization of Bi 2 O 3 /Al nanoenergetics blasted micro-forming system, Defence Technology (2018), https://doi.org/10.1016/j.dt.2018.07.005