Practical Use of Hot-Forged-Type Ti-42Al-5Mn and Various Recent Improvements

Toshimitsu Tetsui

doi:10.3390/met11091361

Abstract

The use of a hot-forged TiAl alloy enables the fabrication of large parts that are difficult to manufacture by casting or isothermal forging. Ti-42Al-5Mn (at%) is the world’s first TiAl alloy in this category and has been used to manufacture practical large-scale structural defense components since around 2010. This paper discusses the developmental status and practical applications of this alloy. In addition, recent developments in process stabilization and improvements in material properties, which have been issues for the practical use of this TiAl alloy in the past, are also discussed.

Highlights

Ti-42Al-5Mn alloy has enabled the manufacture large structural parts the first time the history alloy has enabled the manufacture ofof large structural parts forfor the first time inin the history
Ti-42Al-5Mn is the world’s first TiAl alloy capable of being hot-forged. This alloy has enabled the manufacture of large structural parts for the first time in the history of TiAl alloys
Ti-42Al-5Mn has already been used on the large scale to fabricate a large structural defense-product component for which public disclosure such as displays at international exhibitions is being gradually released

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. After increasing its temperature in a heating furnace, the ingot is removed from the furnace and compressed at high-speed using a hydraulic press while atmospherically cooled This heating, removal, and pressing process is repeated to bring the product closer to the required shape. While this hot-forging method is applied to ordinary metal materials, it is less applicable to TiAl alloys because these alloys are poorly ductile and badly workable, even at high temperatures. TiAl alloy and its practical applications, after which recent research results focusing on the development of new manufacturing processes and new hot-forged TiAl alloys applicable to high-temperature applications are discussed

Developmental History of the Hot-Forged TiAl Alloy

Application

The Development of New Alloys

Conclusion and Future Prospects