Light Metal and Composites Technology: Composites II: Development in Light Weight Alloys
Sponsored by: TMS: Materials Characterization Committee
Program Organizers: Ramasis Goswami, Naval Research Laboratory; Xiaoming Wang, Purdue University; Alex Moser, Naval Research Laboratory; Alan Luo, Ohio State University; Manoj Kolel-Veetil, Naval Research Laboratory; Kumar Sadayappan, CanmetMATERIALS; Tanjore Jayaraman, United States Air Force Academy

Monday 2:00 PM
November 2, 2020
Room: Virtual Meeting Room 28
Location: MS&T Virtual

Session Chair: T Jayaraman, University of Michigan; Alex Moser, US Naval Research Laboratory

2:00 PM  Invited
Developments in Titanium Alloys for Aero-engine Applications: Ramachandra Canumalla¹; ¹Self Employed
    Titanium alloys and their composites were developed and are evolving for applications in aero-engines as fan blades, compressor discs & blades and other parts at least up to 1073K to reduce weight and fuel consumption. Fine structural changes like the precipitation of silicides and/or Ti₃Al or both the phases and other changes in the conventional alloys during service conditions impact properties and there are differences. Further, intermetallic TiAl alloys have been developed and already replaced some heavier nickel base alloys. Various creative cost effective processes are being studied and developed to make these parts with improved microstructures and thus properties. Concepts about more advanced alloys and composites are in the works to push to higher temperature limits. It is attempted to bring out the current state of the understanding of these materials, process technology and possible future trends are presented.

2:20 PM
Effect of Cu Content on Tensile and Low Cycle Fatigue Properties of Cast Al-Cu-Mn-Zr Alloys: Sumit Bahl¹; Xiaohua Hu¹; Jiahao Cheng¹; Eric Hoar¹; Kevin Sisco²; J. Allen Haynes¹; Amit Shyam¹; ¹Oak Ridge National Laboratory; ²University of Tennessee
    Al-Cu-Mn-Zr (ACMZ) is a new family of affordable, cast aluminum alloys that have high temperature microstructural stability up to 350 °C. Higher temperature microstructural stability is necessary to develop next generation automotive engines with increased efficiency. Good hot tear resistance is required in a cast alloy to manufacture complex components. The hot tear resistance of ACMZ alloys improves with Cu content. Here, we present the effect of Cu content (6-9 wt.%) on high temperature tensile and low cycle fatigue properties of ACMZ alloys relevant for automotive engines. The size and volume fraction of brittle grain boundary intermetallic particles increases monotonically in the microstructure with the Cu content. The linkages between grain boundary particles, tensile properties, and low cycle fatigue properties are explained with the help of experimental observations and finite element simulations.

2:40 PM
Metastable f.c.c. Phase and Its Influence on the Soft-magnetic Properties of FeCoNiAlxSix (0.2 < x < 0.5) Alloys: Tanjore Jayaraman¹; Ramasis Goswami²; ¹University of Michigan-Dearborn; ²Naval Research Laboratory
    Significant improvement in soft-magnetic properties of FeCoNiAlxSix (0.2 < x < 0.5) high-entropy alloys is achievable when the alloys are comprised of metastable f.c.c. phase. The nanocrystalline FeCoNiAl0.375Si0.375 alloy fabricated by mechanically alloying the constituent elements resulted in the formation of metastable f.c.c. phase. The metastable phase was stable up to ~800 K and thereafter it dissociated. At ambient temperature, the magnetic saturation (MS) and coercivity (HC) of the alloy was ~91 Am2/kg and ~5 kA/m, respectively. The magnetic characterization from 60 K to 900 K showed a steady decrease in MS, and the HC initially decreased and subsequently increased. The thermally-treated alloy exhibited improvement in the soft-magnetic properties while retaining the nanocrystallinity. While fabrication of the alloys by equilibrium processing facilitates the formation of two phases—b.c.c. and f.c.c., fabrication by mechanical alloying promotes the formation of metastable f.c.c. phase having relatively superior soft-magnetic properties and good thermal stability.

3:00 PM  Invited
A Novel Equiatomic and Non-equiatomic Low-density High Entropy Alloys and Composites: Nandini Singh¹; Yagnesh Shadangi¹; Vikas Shivam¹; Vivek Pandey¹; Varalakshmi Somarauthu¹; Nilay Mukhopadhyay¹; ¹Indian Institute of Technology (BHU) Varanasi
    We have studied equiatomic quinary AlCuFeMnMg, and non-equiatomic octonary AlSiCrMnFeCoNiCu high entropy alloys (HEA) processed through various non-equilibrium routes. The equiatomic MgAlMnFeCu HEA was synthesized by mechanical alloying followed spark plasma sintering (SPS). Similarly, the Al40(SiCrMnFeCoNiCu)60 (at%) HEA was synthesized by vacuum induction melting (VIM). These non-equiatomic HEAs were further subjected to cryomilling (CM) followed by SPS. The phase evolution of these HEA was studied using X-ray diffraction (XRD) and transmission electron microscopy. The morphology and chemical composition of powder particles were examined through SEM and EDX. Thermal stability of these HEAs through in-situ heating XRD and DSC was investigated. The mechanical properties of these alloys were ascertained through instrumented microhardness and compressive testing. The density of these equiatomic and non-equiatomic HEAs was found to be 4.946 ą 0.13 g/cc and 5.086 ą 0.15 g/cc respectively. Various thermodynamic parameters were considered for understanding the phase evolution and their stability.