A strong and deformable in-situ magnesium nanocomposite igniting above 1000 °C

Sravya Tekumalla; Yogesh Nandigam; Nitish Bibhanshu; Shabadi Rajashekara; Chen Yang; Satyam Suwas; Manoj Gupta

doi:10.1038/s41598-018-25527-0

A strong and deformable in-situ magnesium nanocomposite igniting above 1000 °C

Sci Rep. 2018 May 4;8(1):7038. doi: 10.1038/s41598-018-25527-0.

Authors

Sravya Tekumalla¹, Yogesh Nandigam², Nitish Bibhanshu³, Shabadi Rajashekara⁴, Chen Yang⁵, Satyam Suwas³, Manoj Gupta⁶

Affiliations

¹ Department of Mechanical Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore, 117576, Singapore. tvrlsravya@u.nus.edu.
² Department of Metallurgical and Materials Engineering, Indian Institute of Technology Roorkee, Uttarakhand, 247667, India.
³ Department of Materials Engineering, Indian Institute of Science, Bangalore, 560012, India.
⁴ Laboratory of Physical Metallurgy and Materials Engineering, Unité Matériaux Et Transformations, UMR CNRS 8207, Université Lille - 1 Sciences et Technologies, 59650, Villeneuve d'Ascq, France.
⁵ Department of Mechanical Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore, 117576, Singapore.
⁶ Department of Mechanical Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore, 117576, Singapore. mpegm@nus.edu.sg.

Abstract

Magnesium has been trending of late in automobile, aerospace, defense, sports, electronic and biomedical sectors as it offers an advantage in light-weighting. In aluminum, titanium, and steel dominated aerospace and defense sectors, applications of Mg were banned/restricted until recently due to perceived easy ignition and inability to self-extinguish immediately. Strength is generally inversely related to ductility, weak texture and unrelated to ignition resistance, making it challenging to optimize all four concurrently in a material. We address this challenge by designing a low density (~1.76 g.cm^-3) in-situ Mg nanocomposite. It is a resultant of a sequence of in-situ reactions during melt processing and extrusion. The in-situ formed Y₂O₃ nanoparticles exhibit coherency with matrix and lead to development of large amount of elastic and plastic strain fields around them. These nanoparticles and secondary phases (Mg₂Ca and Mg₂Y) are responsible for the nanocomposite's high tensile strength (~343 MPa). A weak texture mediated tensile ductility of 30% and compressive failure strain of 44% is observed. Further, the ignition temperature increased to 1045 °C (near the boiling point of Mg) due to the formation of protective surficial oxide layers aided by the presence of insulating Y₂O₃ nanoparticles, rendering the nanocomposite outperform other traditional commercial Mg-based materials.