Mikrostrukturelle und mechanische Charakterisierung von TiAl Rennsportventilen

Translated title of the contribution: Microstructural and mechanical characterization of TiAl motor sport valves

Research output: ThesisDiploma Thesis


In this diploma thesis valves for racing and high-performance applications consisting of an intermetallic γ-TiAl alloy were examined. Microstructure and mechanical properties of the valves produced by two different manufacturing routes were compared with each other. The production of the raw materials through the newly developed skull-melter-route is superior to the conventional ingot-route regarding the homogeneity of the microstructure. A third generation TiAl alloy was investigated. The major advantage of this intermetallic alloy is its outstanding formability at forging temperatures. Thereby near-net shape semi-finished components can be manufactured. The mechanical characterization of the valves was carried out with rotational bending tests at room temperature and creep tests at temperatures and stresses corresponding to the valves operating conditions. The characterization of the microstructure was conducted using light optical microscopy and scanning electron microscopy. The phase fractions of the γ-TiAl, βo-TiAl and α2-Ti3Al phases were determined at room temperature and compared at the different states by means of X-ray diffraction. The surfaces of the fractured rotational bending specimens were examined using stereo- and scanning electron microscopy. The occurring defect sizes were compared with an estimation and showed accordance to the measurement. To determine the microstructure during the forging process of the valves, heat treatment studies at forging temperatures were carried out followed by water quenching. Based on the results from this study the specifics of the different production routes were shown. Introducing the skull-melter-route represents a promising way to replace the previous ingot-route. Moreover, mechanical properties can be enhanced due to the higher homogeneity of the material.
Translated title of the contributionMicrostructural and mechanical characterization of TiAl motor sport valves
Original languageGerman
  • Mayer, Svea, Co-Supervisor (internal)
  • Klein, Thomas, Co-Supervisor (internal)
  • Clemens, Helmut, Supervisor (internal)
Award date18 Dec 2015
Publication statusPublished - 2015

Bibliographical note

embargoed until 05-11-2020


  • TiAl
  • valve
  • motor sports
  • microstructure
  • mechanical properties
  • process development

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