Potentials of Ceramic Die Materials for Isothermal Forging Purposes of a Titanium Alloy

Abstract

The machining of titanium alloys is challenging in every aspect. In order to avoid waste material by cutting processes and to improve mechanical properties, forming processes offer many advantages but harbor also challenges. To face these challenges, especially techniques like isothermal forging are promising methods. Isothermal forging is an appropriate process for achieving a microstructure with excellent properties for high performance applications in aviation technology and turbine construction. One of the main challenges in this special process is the determination of a tool material with a high temperature resistance as well as a high resistance against the work load of forging processes. Given their high hardness, temperature resistance and wear resistance, technical ceramics feature properties classifying them as generally suitable for this application. This article deals with the complete design of an isothermal forging process with ceramic tool material for titanium forming. The material characterization of the forming material by flow curve determination is performed to receive data for FE analyses. Afterwards, a ceramic tool system for isothermal forging is designed and manufactured. The tests show that especially the brittleness of technical ceramics restricts their application as tool material for isothermal titanium forming. Additional investigations on isothermal forging using carbide metal as tool material show the benefit of isothermal titanium forging. The results of metallographic analyses are given.