Seminar on Strength and Fracture Resistance in Multicomponent Alloys and Additive Manufactured Materials

18 May 2022 03.00 PM - 04.00 PM LHN-LT (LHN-B1-15, The Arc, 63 Nanyang Drive, Singapore 636922) Current Students, Public

Dr Bernd Gludovatz
 
Scientia Associate Professor

School of Mechanical and Manufacturing Engineering, UNSW Sydney

This seminar will be chaired by Prof Upadrasta Ramamurty.

Seminar Abstract

Damage tolerant materials with a good combination of strength and toughness are key for the increasing complexity of structural applications and a long sought-after goal for both mechanical engineers and materials scientists. Unfortunately, these properties are generally mutually exclusive and the development of new alloys with damage tolerant design has traditionally been a compromise between hardness and ductility. This talk will focus on recently developed advanced metallic materials that show good combinations of strength and toughness; compositionally complex alloys, often termed high-entropy alloys (HEAs), and bulk-metallic glasses (BMGs). HEAs are known for their ability to crystallize as single-phase solid solutions with simple crystal structures despite containing high concentrations of elements with very different crystal structures. BMGs, on the other hand, are known for their excellent combinations of high strength, low stiffness, and large elastic strain limits. Major drawbacks for their use in engineering service, however, are highly variable fracture toughness values and ductilities which can be entirely different for loading in tension, compression or bending. We will examine how failure resistance in compositionally modified variations of the face-centered cubic CrMnFeCoNi Cantor alloy, the most studied HEA to date, develops at sub-zero temperatures and how the body-centered cubic TiZrNbHfTa results with an increase in both yield and ultimate tensile strength without loss in ductility after irradiation with He2+ ions. In terms of BMGs, we will discuss how structural modifications through processing via high-pressure torsion (HPT) and precise heat treatments affect yield, failure strength, and plastic strain in tension, and more importantly, have the ability to entirely change the failure characteristics of a metallic glass. Finally, we will discuss how additive manufacturing can be utilized to overcome some of the limitations with BMGs and evaluate some of the benefits and drawback this processing method imposes on structural materials

Speaker’s Biography​

Bernd Gludovatz is a Scientia Associate Professor in the School of Mechanical and Manufacturing Engineering at UNSW Sydney. He received his M.S. and his Ph.D. as a student of Prof. Reinhard Pippan at the University of Leoben, Austria, both in Materials Science and Engineering. After that, he worked as a post-doctoral fellow of Prof. Robert O. Ritchie at the Materials Sciences Division of the Lawrence Berkeley National Laboratory in the US. His research interests are in the multi-scale mechanical behavior of materials, particularly fracture and fatigue of advanced metallic alloys, nature-inspired ceramic composites and biomaterials.