Analysis of the Microstructure and Mechanical Properties during Inertia Friction Welding of the Near-\u03b1 TA19 Titanium Alloy

Yanquan Wu,Yunlei Li,Chunbo Zhang,Jun Zhou,Wu Liang

doi:10.1186/s10033-020-00507-6

Abstract

The current research of titanium alloy on friction welding process in the field of aero-engines mainly focuses on the linear friction welding. Compared to the linear friction welding, inertial friction welding of titanium alloy still has important application position in the welding of aero-engine rotating assembly. However, up to now, few reports on inertial friction welding of titanium alloy are found. In this paper, the near-alpha TA19 titanium alloy welded joint was successfully obtained by inertial friction welding (IFW) process. The microstructures and mechanical properties were investigated systematically. Results showed that the refined grains within 15‒20 μm and weak texture were found in the weld zone due to dynamic recrystallization caused by high temperature and plastic deformation. The weld zone consisted of acicular α′ martensite phase, αp phase and metastable β phase. Most lath-shaped αs and β phase in base metal were transformed into acicular martensite α′ phase and metastable β phase in thermo-mechanically affected zone and heat affected zone. As a result, the microhardness of welded joint gradually decreased from the weld zone to the base metal. Tensile specimens in room temperature and high temperature of 480 °C were all fractured in base metal illustrating that the inertia friction welded TA19 titanium alloy joint owned higher tensile strength compared to the base metal.

Highlights

Titanium alloys, as a significant structural metal material, are widely applied in aerospace and other fields owing to its low density, high specific strength, low elastic modulus, excellent corrosion resistance and high heat resistance [1,2,3,4,5]
Ballat-Durand et al [30] found that the β→α′ martensitic transformations during cooling resulted in a strong texture in the core of the joint with the {0001} plane paralleling with the friction plane {xy}, and the direction aligning with the transversal direction when they researched the microstructure changes during linear friction welding of Ti6242 titanium alloy
The weld zone (WZ) is characterized as dynamically recrystallized region or transformed and recrystallized zone, where the materials experience a thermal-mechanical deformation above β-transus temperature [42]

Summary

Introduction

As a significant structural metal material, are widely applied in aerospace and other fields owing to its low density, high specific strength, low elastic modulus, excellent corrosion resistance and high heat resistance [1,2,3,4,5]. The friction welding of near-β and α + β titanium alloys, such as Ti6Al4V, Ti6246, Ti17, and so on has been widely investigated in nearly research. Liu et al [29] researched the texture evolution in α + β titanium alloy joint by thermal and mechanical of inertia friction welding. Ballat-Durand et al [30] found that the β→α′ martensitic transformations during cooling resulted in a strong texture in the core of the joint with the {0001} plane paralleling with the friction plane {xy}, and the direction aligning with the transversal direction when they researched the microstructure changes during linear friction welding of Ti6242 titanium alloy. The investigation on microstructure texture and mechanical properties in IFW of TA19 titanium alloy is hardly found. The findings in the work will provide key experimental date and theoretical guidance for inertia friction welding of TA19 alloy in industrial application

Materials and Methods

Results and Discussion

Conclusions