Hole Making by Electrical Discharge Machining (EDM) of γ-TiAl Intermetallic Alloys

Abstract

Due to their excellent strength-to-weight ratio and corrosion and wear resistance, γ-TiAl alloys are selected for aerospace and automotive applications. Since these materials are difficult to cut and machine by conventional methods, this study performed drilling tests using Electro Discharge Machining (EDM) to compare the machinability between two different types of γ-TiAl: extruded MoCusi and ingot MoCuSi. Different electrode materials and machining parameters were tested and wear, surface hardness, roughness and integrity were analyzed. The results indicate that extruded MoCuSi is preferable over MoCuSi ingots.

Drilling Process in γ-TiAl Intermetallic Alloys

“…After model calibration, validation tests were done, showing a good agreement.Experimental drilling tests done to evaluate the machinability of these difficult-to-cut materials (the high cost of the tested materials (approx. 400 €/kg) limited the number of tests and a stronger experimental design) show that the obtained cutting coefficients present a quasi-linear dependence on the pilot hole D 0 for the axial force F z , while a cubic is more suitable in the case of T c .Machining problems during drilling tests confirm that these are very brittle materials, so operational parameter determination is essential for chipping and cracking avoidance of components during machining processes [41,42]. Experiments demonstrated large differences between the more conventional Ti6Al4V alloy and the three γ-TiAl intermetallic alloys.…”

Drilling of γ-TiAl Intermetallic Alloys. Mechanistic Model to Predict Cutting Force and Torque

“…Three manufactured presentations for these alloys are in the market, the TNB alloy, the alloy solidified as ingot, and the alloy extruded after solidification. These are very brittle materials, so a special care must be paid to avoid the chipping and cracking of components during machining processes [35][36]. Besides, two serious disadvantages during their processing are their great sensibility to the impurity during the foundry process and so, high production costs.…”

Experimental Study of Tool Wear in Electrochemical Discharge Machining

“…With the development of micro-electromechanical system (MEMS) and microfluidics technologies, higher technical requirements are raised for the microfabrication of non-conductive materials, such as glass, ceramics, and carbon fiber-reinforced polymer (CFRP) material. ECDM has rapidly developed and been studied as an important processing method [7][8][9]. Especially for the micro-machining of hard and brittle material with complicated 3D structures, many studies have been conducted to improve the machining precision, such as changing the motion control approach [10], parameter optimization using the response surface method [11] and building the tool wear simulation model [12].…”