Wire Electric Discharge Machining Induced Surface Integrity for Ni_55.95Ti_44.05 Shape Memory Alloy

Abstract

The current study unveils the variation of surface integrity aspects (micro-hardness, surface crack density, and surface characteristics) for Ni55.95Ti44.05 shape memory alloy (SMA) with wire electric discharge machining (WEDM) process parameters, namely, pulse off time, wire tension, spark gap voltage, wire feed rate and pulse on time. The experimental results reveal that micro-hardness displays direct relationship with spark gap voltage, pulse on time, and pulse off time whereas surface crack density shows direct relationship with pulse on time and inverse trend with spark gap voltage and pulse off time. Wire tension and wire feed rate show trivial effect on both surface crack density and micro-hardness. Machined surface comprises crater, micro-cracks, micro-voids, pockmarks, and lumps of debris while inspecting through a scanning electron microscope (SEM). During energy-dispersive X-ray spectroscopy (EDS) analysis, the foreign elements namely carbon, oxygen, copper and zinc were also detected on the surface. The high energy density at higher pulse on time adversely affects the surface morphology. The formation of large size craters (deep and wide) with more cracks on the machined surface were observed at lower pulse off time as compared to higher pulse off time.

Process Modelling and Optimization using ANN and RSM during WSEM of Ni51.59Ti48.41 shape memory alloy

“…These findings are similar to the results reported by Bisaria and Shandilya. 6 The influence of S V on response MRR is also manifested in Figure 3. For a certain values of S ON , S OFF and W F , MRR increases gradually until the mid-point of S V and then gradually decreases.…”

“…Recently Bisaria and Shandilya (2020) 6 performed a detailed study on WEDM of Ni 55.95 Ti 44.05 . They found that micro-hardness of machined surface is directly affected by the machining parameters, i.e., spark on-time, spark off-time and spark gap voltage.…”

“…Biomedical industries need complex shapes implants, and wire spark erosion machining (WSEM) is well known for producing complex shapes on a mass scale at a low cost. 6 Therefore WSEM has been selected for processing of Ni-Ti SMAs. WSEM is a process in which material is removed from the workpiece surface due to a series of sparks.…”

Parametric Optimization of Wire Electrical Discharge Machining in AA7075 Metal Matrix Composite

“…Table 2 shows the identi ed experimental data for conducting the experiment using MINITAB 19 software. Experimental levels of parameters were selected based on the studies of Bisaria and Shandilya 2020 [31].…”

Multicut technology used in WEDM machining of Mar-M247

“…They tried to reveal the effect of the variable parameters of EDWC such as wire feed, pulse on and off time, spark gap voltage, wire tension on foreign element atomic content, and recast-layer thickness using the one-factor-at-a-time approach. Bisaria and Shandilya 23 investigated the various surface integrity aspects, such as micro-hardness, surface characteristics, and surface crack density while machining the NiTi shape memory alloy in the WEDM process taking into account a range of various process parameters. The results of the experiments revealed that surface crack density displays a direct relationship with a pulse on time, micro-hardness shows a direct relationship with a pulse on and off time and gap voltage, and the inverse trend shows it with pulse off time and gap voltage.…”