Mechanical and microstructural analysis of ultrasonically assisted induction-brazed TiAl6V4 joints

Abstract

This paper focuses on the process of ultrasonically assisted induction brazing with regard to titanium brazing. The titanium alloy TiAl6V4 was brazed using an aluminum-based filler alloy (AlMg2.5Cr0.3). It was apparent that the layer thickness of the brazing foil as well as the brazing temperature and the intensity of the ultrasound are significant influencing factors of the combined brazing process and microstructure. It is the aim of this paper to draw conclusions from the microstructural and mechanical investigations of the brazed joint about the process parameters, which are crucial for the properties and quality of the joint. The evaluation of the microstructure of the joint was conducted by means of metallographic investigations and results obtained by means of scanning electron microscopy. Besides mechanical microhardness measurements, strength investigations were conducted in order to evaluate the quality of the joint. Furthermore, the results of conventional vacuum brazing processes were correlated in order to be able to better facilitate and understand the adapted induction brazing process.

Low‐Temperature Brazing of Titanium Using Al‐Based Filler Alloys

“…Tillmann et al [37] studied the ultrasound-assisted brazing of Ti-6Al-4V using Al-2.5Mg-0.3Cr filler and induction heating.…”

“…Elrefaey et al [38] used, for instance, an apparatus where the horn was installed vertically, and the sample which was mounted into a steel holder was under 0.2 MPa pressure as a result of the horn weight ( Figure 6). While, Tillmann et al [37] used overlapped brazing joints with a torque of 8 Nm introduced by a screw connection.…”

“…Many Al-based filler alloys have been developed since that time, and many attempts were made in pursuit of achieving suitable brazing conditions. Titanium was brazed to itself and to aluminum alloys by Al-based fillers using an oxyacetylene torch with flux [30,33], in high-purity argon [10,33], in vacuum [28][29][30][31][34][35][36], and in air conditions: in fluxless process assisted by the ultrasonic vibration (USV) [37][38][39] or by additional pressure [40]. Investigating and improving the mechanical properties of the produced joint through a careful design of the brazing cycle and controlling the intermetallic compound formation/diffusion zone were among the primary explored objectives in brazing titanium and its alloys.…”

“…Using USV in brazing is an attractive assisting tool [37][38][39][52][53][54][55][56][57][58]; however, studying the combined effects of USV with the technological parameters of brazing process and developing a joint interface more compatible with the USV have not yet received an adequate attention. e focus in this review will be on the titanium/aluminum interface which includes Albased filler alloys for brazing titanium/titanium and titanium/aluminum parent (base) components, taking into consideration the technological parameters and procedures.…”

Compressive Strength and Interface Microstructure of PCBN Grains Brazed with High-Frequency Induction Heating Method

“…Furthermore, the dimension accuracy of abrasive wheel is always affected greatly because the whole abrasive tool has to be heated in the vacuum resistance furnace. On the contrary, the high-frequency induction brazing technology has some great advantages, such as rapid heating rate and locally heating, which could provide a good prospect to prepare the abrasive wheels with large diameter (i.e., 400 mm) and high accuracy in dimension [16][17][18][19].…”