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In this work, quantitative assessment of surface damage in terms of parameters like surface crack density and recast layer thickness in wire electrical discharge machining (WEDM) process has been undertaken. The effect of processing conditions on crack formation is studied using scanning electron microscope. Surface crack density and recast layer thickness analysis in terms of machining parameters such as pulse on time, pulse off time, peak current, spark gap voltage significantly deteriorate the microstructure of machined samples, which produces the deeper, wider overlapping craters, pockmarks, globules of debris andmicro cracks. The microstructure analysis ofWEDMsurface was based upon the theory of electrical discharge phase and metallurgical physics. It is found that the pulse on time, pulse off time and peak current are the most dominating parameters for both surface crack density and recast layer thickness. [ABSTRACT FROM AUTHOR]

This article presents an experimental investigation of wire cut electro discharge machining of pure titanium. The marvelous characteristics of pure titanium such as its compatibility and noticeable physical, mechanical and biological performances have led to their increased application in various industries especially in seawater pipings, heat exchangers, implants, prosthesis, airframe and aircraft engine parts over the last 50 years. However, due to low thermal conductivity of titanium and their reactivity with cobalt in most tool materials, there are some difficulties in machining titanium and its alloys by conventional machining. On the other hand, unconventional machining processes especially wire cut electro discharge machining are more appropriate techniques for machining difficult-to-machine materials like pure titanium. This research work is mainly focused on microstructure analysis in terms of machining parameters such as pulse on time, pulse off time, peak current, spark gap using energy-dispersive X-ray, scanning electron microscope and X-ray diffraction techniques. The present results reveal that pulse on time and peak current significantly deteriorate the microstructure of machined samples, which produces the deeper, wider overlapping craters, pockmarks, globules of debris and micro-cracks. The microstructure analysis of rough cut surface was based upon the theory of electrical discharge phase and metallurgical physics. [ABSTRACT FROM PUBLISHER]

The wire electric discharge machining process is an alternative for machining of the high strength temperature resistant materials. The present research work is mainly focused on the investigation of integrity of the work surface and wire electrode surface after machining with WEDM. Experimental results showed that pulse-on time, pulse-off time and peak current significantly affected the surface integrity with the formation of deep-wide overlapping craters, pock marks, debris, micro-cracks and recast layer. Both carbides and oxides were formed either in free form and/or in compound form due to decomposition of de-ionized water, machined samples and wire material. The compounds like titanium dioxide (rutile)(TiO2),(TiO0.325),Ti2O3, Ilmenite(Fe2Ti4O), titanium carbides(TiC)and copper titanium dioxide(Cu3TiO4)were formed due to phase transformations that were analyzed through X-ray diffraction and energy dispersive X-ray method. The effect of process parameters on the wear of wire surface has also been considered. [ABSTRACT FROM AUTHOR]

This research work explores the relationship of machining parameters such as pulse on time (Ton), pulse off time (Toff), peak current (Ip), spark gap voltage, wire feed and wire tension on the material removal rate, wire wear ratio and surface roughness for pure titanium in wire electric discharge machining process. The Box–Behnken design had been utilized to plan the experiments, and response surface methodology was employed for developing the empirical models. The peak current, spark gap voltage, pulse on time, pulse off time and interaction between pulse on time and peak current affected the surface roughness significantly. Multi-response optimization of process parameters was obtained using desirability approach. Furthermore, the selected machined samples were analyzed using energy-dispersive X-ray analysis, scanning electron microscope and X-ray diffraction techniques. The predictions from this model were validated by conducting confirmatory experiments. [ABSTRACT FROM PUBLISHER]

Microstructural evolution and interfacial reactions during active metal vacuum brazing of Ti (grade-2) and stainless steel (SS 304L) using a Ag-based alloy containing Cu, Ti, and Al was investigated. A Ni-depleted solid solution layer and a discontinuous layer of (Ni,Fe)TiAl intermetallic compound formed on the SS surface and adjacent to the SS-braze alloy interface, respectively. Three parallel contiguous layers of intermetallic compounds, CuTi, AgTi, and (Ag,Cu)Ti, formed at the Ti-braze alloy interface. The diffusion path for the reaction at this interface was established. Transmission electron microscopy revealed formation of nanocrystals of Ag-Cu alloy of size ranging between 20 and 30 nm in the unreacted braze alloy layer. The interdiffusion zone of β-Ti(Ag,Cu) solid solution, formed on the Ti side of the joint, showed eutectoid decomposition to lamellar colonies of α-Ti and internally twinned (Cu,Ag)Ti intermetallic phase, with an orientation relationship between the two. Bend tests indicated that the failure in the joints occurred by formation and propagation of the crack mostly along the Ti-braze alloy interface, through the (Ag,Cu)Ti phase layer. [ABSTRACT FROM AUTHOR]

This research work mainly focused on experimental investigation on material transfer mechanism in WEDM of pure titanium. The effects of machining parameters such as pulse on time, pulse off time, peak current, spark gap voltage, wire feed, and wire tension on the material removal rate (MRR), overcut, and surface roughness for pure titanium in WEDM process were explored. The selected machined samples were analyzed using energy dispersive X-ray analysis, scanning electron microscope, and X-ray diffraction techniques. It was observed from the results that a significant material transfer occurred from the dielectric, as well as tool, electrode on the work surface either in free form and/or in compound form. Also the multi response optimization of process parameters was done using desirability approach. The predictions from this model were validated by conducting experiments. [ABSTRACT FROM AUTHOR]