Browsing by Author "Kalinga, T."

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    Experimental investigation of the pseudoelastic behavior on zirconium modified Cu-Al-Be shape memory alloys for seismic applications
    (IOP Publishing Ltd, 2022) Kalinga, T.; Murigendrappa, S.M.; Kattimani, S.
    This paper examines the effect of 0.05-0.3 wt.% of zirconium-doping on microstructure, transformation temperatures, tensile properties, and pseudoelastic behavior of the parent β1 -phase Cu87.93-Al11.5-Be0.57 shape memory alloys (SMAs). Results reveal that alloying zirconium in the evaluated SMA samples exhibits an excellent grain refinement up to 0.15 wt.%. Further, higher additions of Zr ≥ 0.2 wt.% lowers the grain refinement efficiency due to precipitates agglomeration. Larger the size and volume fraction of Al3Zr precipitates led to higher transformation temperatures. Tensile properties were improved with Zr-doping, resulting enhancements in the maximum tensile strength and ductility with the addition of 0.15 wt.% Zr. The alloy with 0.05 wt.% of Zr-dope showed a good pseudoelastic strain recovery of deformation strain and then lowered by retaining large residual strain, indicating deterioration in the pseudoelasticity of SMAs. © 2022 IOP Publishing Ltd.
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    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.
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    Role of alloying additions on phase transformations, mechanical and pseudoelastic behavior of Cu-Al-Be shape memory alloys
    (Elsevier Ltd, 2022) Kalinga, T.; Bala Narasimha, G.; Murigendrappa, S.M.; Kattimani, S.
    In this study, the influence of alloying additions on phase transformations, microstructure, transformation temperatures, mechanical properties, and pseudoelastic behavior of polycrystalline Cu-Al-Be shape memory alloy has been investigated. Four different SMAs were prepared in the range of 11.0–11.8 wt.% of aluminum and 0.5–0.6 wt.% of beryllium. Results reveal that the alloying of Al ≥ 11.5 wt.% and Be ≥ 0.57 wt.% forms austenite β1(DO3) at room temperature. An increase in both aluminum and beryllium decreases the transformation temperatures, and Cu-11.5Al-0.57Be SMA exhibits smaller energy differences (ΔH) between austenite and martensite. Alloying aluminum and beryllium didn't exhibit significant improvement in mechanical properties due to the existence of coarse grains. Maximum pseudoelasticity of 4% was achieved in Cu-11.5Al-0.57Be SMA with a retained strain of 0.192%. © 2021