Faculty Publications
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Item An investigation on the properties of boron modified Cu–Al–Be polycrystalline shape memory alloys(Elsevier Ltd, 2020) Bala Narasimha, G.; Murigendrappa, S.M.Effect of microalloying of boron (B) i.e., 0.02–0.15 wt% and the variation of composition of Al and Be from 11.3 to 11.9 wt% and 0.41–0.44 wt% respectively, has been investigated on the grain refinement and shape memory properties of polycrystalline Cu–Al–Be shape memory alloy. The tests have been carried out for microstructure, morphology, phases, crystal structure, phase transformation temperatures and shape recovery ratio. The investigation results in boron has strong impact on grain refinement with minimal addition, followed by Al and Be. AlB2 acts as heterogeneous nucleation site in grain refinement and it increases with increase in B and Al. Transformation temperatures increases with boron up to 0.08 wt% and then decreases, whereas increase in Al and Be decreases the temperatures. Doping and increasing of boron up to 0.15 wt% exhibits complete shape recovery, whereas Be < 0.42 wt% and Al < 11.8 wt% exhibits poor recovery ratio. © 2020 Elsevier B.V.Item Pseudoelastic Behavior of Boron-Doped ?1 -Type Cu-Al-Be Shape Memory Alloys(Springer, 2021) Kalinga, T.; Murigendrappa, S.M.; Kattimani, S.This paper examines the influence of 0-0.2 wt.%B-doping on the microstructure, mechanical properties, and pseudoelastic behavior of Cu-Al11.5-Be0.57 shape memory alloys (SMAs). This microstructure study reveals that the addition of boron leads to significant grain refinement in ?1-type polycrystalline Cu-Al-Be SMAs. A maximum refinement size of 50 µm was achieved with the addition of 0.15 wt.%B. The fine-grained (Cu-Al11.5-Be0.57)-B0.15 SMA with serrated grain boundaries exhibited the maximum enhancement of ultimate tensile strength, 744.65 ± 29.34 MPa, and ductility of 21.93 ± 0.56%. The fracture morphology revealed the transformation of intergranular to transgranular fracture in the SMAs with boron-doping. Maximum pseudoelasticity of 4% was achieved in the SMA with 0.15 wt.%B and suits as a damper in seismic applications. © 2021, ASM International.Item An experimental evaluation of the microstructure, mechanical and functional fatigue properties of the boron-doped Cu-Al-Be SMA wires(Elsevier Ltd, 2021) Singh, R.K.; Biswas, P.; Murigendrappa, S.M.; Kattimani, S.An experimental evaluation of the microstructure, mechanical and functional fatigue properties of the Cu-11.70Al-0.45Be doped with Bx (x = 0.05, 0.10, 0.12, and 0.14 wt%) SMA wires has been carried out. The experiments were performed to investigate microstructure, phase/precipitates, and transformation temperatures for both as-cast and wire samples. Furthermore, tensile properties, shape recovery ratio, and functional fatigue evaluation have also been carried out for the wire samples. The investigation shows that the addition of the minor amount of boron and secondary processes involved during the specimen preparation induced excellent grain refinement. The addition of boron decreased transformation temperatures; however, there was not a considerable change observed due to the secondary process. It was observed that tensile properties increases with the boron addition, and complete shape recovery was observed for all the selected alloys. Finally, functional fatigue tests were conducted under constant stress condition and observed that the number of cycles until the failure has increased and more distance recovery was achieved with an increase in boron doping. © 2021