Brazing of magnesium alloy and austenitic stainless steel using a copper-filler, deposited by means of an arc-PVD process

摘要

Currently, magnesium is frequently used in industrial manufacturing processes as well as for many industrial products due to its availability and its lightness. For constructive applications, especially in the automotive and aerospace industries, magnesium alloys are often applied due to their superior properties when compared to pure materials. However, flux-free bonding these alloys is challenging because of heavy oxidation and intermetallic segregations in the joining gap. Thus, adequate manufacturing processes are required, especially to produce magnesium and steel hybrid concepts with adapted properties. For this study, the magnesium alloy AZ 31 was brazed to the austenitic CrNi-steel AISI 304. Copper layers, with varying thicknesses, were deposited by means of an arc-PVD coating process and were used as filler material. The samples were brazed at 520℃ for 5, 10, 15, and 30 min. in a shielded gas atmosphere, utilizing inductive heating. The microstructure and the phase composition of the brazed joints were analyzed metallographically by means of a scanning electron microscope (SEM) and energy dispersive X-ray (EDX). Furthermore, the mechanical properties of the brazements were determined in hardness- and shear strength measurements, which showed that the most effective joints achieved higher strengths than the base material.