Parametric study on the recast layer during EDWC of a Ni-rich NiTi shape memory alloy

Abstract

Shape memory alloys (SMAs) have exceptional properties, namely, shape memory effect, superelasticity and other enriched physical and mechanical properties. The conventional machining of these alloys is associated with several severe difficulties. Electric discharge wire cutting (EDWC), an advanced machining process, is utilized to machine Ni50.89Ti49.11 SMA under this investigation. The aim of this investigation was to reveal the effect of EDWC variable parameters such as pulse on time ( TON), wire feed (WF) rate, spark gap voltage (SV), wire tension (WT) and pulse off time ( TOFF) on recast-layer thickness (RLT) and a foreign element atomic content (FEAC) using the one-factor-at-a-time approach. Scanning electron microscope equipped with energy dispersive X-ray spectroscopy facility was utilized to analyse RLT and FEAC. RLT and FEAC are varied linearly and nonlinearly respectively with TON, TOFF and SV. A thick recast layer with a high percentage of FEAC was formed on the machined surface of Ni50.89Ti49.11 SMA at a higher TON and a lower TOFF and SV. However, RLT and FEAC are slightly varied with WF and WT.

Wire Electric Discharge Machining Induced Surface Integrity for Ni55.95Ti44.05 Shape Memory Alloy

“…1,2 Ni-rich NiTi SMAs have been extensively used in biomedical, aerospace and robotics industries 3–5 because of their exclusive properties for example, high corrosion resistance, shape memory effect, superelasticity, high specific strength, and smooth surface properties as compared to equiatomic NiTi SMAs. 6,7 The casting and powder metallurgy are the commonly used techniques for the manufacturing of SMA. Recently, the additively manufactured SMAs’ components are gaining more acceptability.…”

Study on crater depth during material removal in WEDC of Ni-rich nickel–titanium shape memory alloy

“…Currently, SMAs are being widely used in various sectors, such as robotics, biomedical, aerospace, and other important industries due to their outstanding properties [2,3]. Ni-rich NiTi SMAs show better superelasticity and shape memory effect compared to equiatomic NiTi SMAs because of higher intrinsic strength, and they can be precipitation-hardened [4][5][6]. Conventional machining of NiTi SMAs is the most challenging task because of the high reactivity of titanium which causes poor surface finish, high tool wear, and high machining time [7,8].…”

Influence law and optimization analysis of technological parameters of TC4 titanium alloy on water cavitation peening

“…The influence of WCP strengthening process on the surface microhardness is the dimensionless target distance, the incident pressure, the peening time, the nozzle diameter in sequence. (2) The peening time has the greatest effect on surface strengthening of TC4 titanium alloy, while the nozzle diameter has the least effect on surface strengthening of TC4 titanium alloy. Therefore, when WCP process to strengthen the surface of metal materials is used, the first factor considered is the peening time, followed by the incident pressure and the dimensionless target distance.…”

“…Therefore, TC4 titanium alloy structural parts need to be surface strengthened. 1,2 Water Cavitation Peening (WCP) is a kind of the peening technology, which uses the collapse of cavitation bubble to generate high pressure and strong micro-jet shock wave. The cavitation bubble group is made collapse to have great potential on the material surface modification by micro-jet shock wave.…”