Prediction of Fracture Initiation in Hot Compression of Burn-Resistant Ti-35V-15Cr-0.3Si-0.1C Alloy

Abstract

An important concern in hot working of metals is whether the desired deformation can be accomplished without fracture of the material. This paper builds a fracture prediction model to predict fracture initiation in hot compression of a burn-resistant beta-stabilized titanium alloy Ti-35V-15Cr-0.3Si-0.1C using a combined approach of upsetting experiments, theoretical failure criteria and finite element (FE) simulation techniques. A series of isothermal compression experiments on cylindrical specimens were conducted in temperature range of 900-1150°C, strain rate of 0.01-10 s 21 first to obtain fracture samples and primary reduction data. Based on that, a comparison of eight commonly used theoretical failure criteria was made and Oh criterion was selected and coded into a subroutine. FE simulation of upsetting experiments on cylindrical specimens was then performed to determine the fracture threshold values of Oh criterion. By building a correlation between threshold values and the deforming parameters (temperature and strain rate, or Zener-Hollomon parameter), a new fracture prediction model based on Oh criterion was established. The new model shows an exponential decay relationship between threshold values and ZenerHollomon parameter (Z), and the relative error of the model is less than 15%. This model was then applied successfully in the cogging of Ti-35V-15Cr-0.3Si-0.1C billet.

Solidification Effect on the Microstructure and Mechanism of Laser‐Solid‐Forming‐Produced Flame‐Resistant Ti–35V–15Cr Alloy

“…In the early 1990s, Pratt and Whitney developed a commercial flame‐resistant titanium alloy, Ti–35V–15Cr (in wt%, the same hereafter unless specified), called Alloy C . Zhang et al studied the recrystallization mechanism of flame‐resistant Ti–35V–15Cr–0.3Si–0.1C alloy. Especially, the influence of titanium carbide on the microstructure evolution during hot compression was investigated, and the fracture initiation was predicted combining with experiments, theoretical failure criteria, and finite element simulation (FEM).…”