Prevalent mode II fracture assessment of inclined U-notched specimens made of tungsten-copper functionally graded material

Abstract

In the present paper, for the first time, the fracture of notched components made of tungsten-copper functionally graded material (W-Cu FGM) has been assessed both theoretically and experimentally. W-Cu FGM is one of the most prominent FGMs, which has been utilized as plasma facing component as well as heat sink in microelectronic systems. In this investigation, first, six-layered W-Cu FGM specimens were produced by powder metallurgy technique. The powders were stacked layer-by-layer into a D2 steel die and pressed at room temperature and sintered in a vacuum furnace at 1050°C. Two extremes of the fabricated specimens were pure copper and a tungsten-based alloy (WBA) which its chemical composition was W-Ni-Mn-Cu respectively as 90–4–3.33–2.67wt.%. A number of fracture experiments were performed on beam shaped specimens weakened by inclined U-notches under prevalent mode II loading for various notch tip radii and depths.Next, the averaged strain energy density criterion over a well-defined control volume was utilized to predict critical loads. The boundary of the control volume was evaluated using a numerical method.The effect of notch tip radius and notch depth on the fracture load was assessed. In this paper, the values of mode mixity (χ) more than 0.8 have been taken into consideration. This contribution demonstrates that SED works well on U-notched FGM components under prevalent mode II loading.