Design and processing of next-generation complex alloys for structural applications (16/11/23)
Speaker and Affliation:
Dr. Saurabh Nene
Advanced Materials Design and Processing Group, Department of Metallurgical and Materials Engineering,
Indian Institute of Technology Jodhpur, Karwar, Jodhpur, Rajasthan 342037 India
When?
16th November, 2023 (Thursday), 3.00 PM (India Standard Time)
Where
K I Vasu Auditorium, Dept. of Materials Engineering, IISc, Bangalore
Abstract:
The design of high entropy alloys (HEA) opened a new avenue of alloy development almost two decades ago providing an abundant compositional space. The evolution in HEA design from entropy-centric to phase-centric changed the focus from HEA to complex concentrated alloys (CCAs) and displayed stability of either of three major phases namely f.c.c., h.c.p. and b.c.c. solid solutions with minor presence of high entropy intermetallic phases in alloy microstructure. With time, the design philosophy of CCAs is termed differently such as equiatomic, eutectic, metastable, and flexible which mainly show synergistic use of fundamental metallurgical principles with CCA theory for the design of respective alloys. In line with that, the present work attempts the design of next-generation complex concentrated alloys for four main categories of metals/alloys namely Fe, Ti, Cu, and Ni/Co based alloys. The design of Fe containing HEA displayed multifunctionality by having five properties (formability, strength-ductility synergy, fatigue resistance, corrosion resistance, and electrical resistivity) better/comparable than its steel counterparts whereas Ti containing as-cast HEA for the first time revealed more than 50 % tensile elongation while having more than 90% compressive formability with an exceptional specific strength. Co and Ni containing HEA showed remarkable high temperature oxidation resistance and specific strength at temperatures greater than 800 Deg C in spite of the absence of any refractory element in the alloy whereas Cu containing complex alloy demonstrated extreme strength-ductility synergy by two phases strengthening as a result of prevalent spinodal decomposition in the alloy. Thus, current work provides a new direction in designing future complex alloys and making them closer to use in structural applications in a much cost-effective way.