Study of the effect of brazing on mechanical properties of aluminum alloys for automotive heat exchangers

Abstract

Automotive heat exchangers enable the engine to operate at acceptable temperatures. The quality of these heat exchangers plays a key role in vehicle performance because they ensure the integrity of the engine, and can cause significant mechanical complications in case of malfunction. From manufacturing stand point view, the general behavior of the structure in controlling the various modes of damage to heat exchangers becomes an indisputable challenge (influence of the process assembly, design, etc.). The evolution of materials used, in particular through the different alloy types, brazing operational parameters and part designs could be used to tackle these challenges. This imposes the constant need to control the conditions of use and to understand the braze alloy mechanisms to provide the best possible solutions for manufacturing automotive heat exchangers. An experimental study is conducted by simulating the brazing of alloys and the mechanical properties after brazing as well as re-brazing. Aluminum alloys with different compositions and metallurgical conditions that are used in the automotive heat exchanger industry are used in this study to understand the effect of brazing on the mechanical properties. The experiments conducted and results obtained show the degradation in the mechanical properties after brazing. But interestingly the mechanical properties of the re-brazed alloys studied are very similar to the first brazing cycle. This generates further interest in exploring more about the mechanical properties of re-brazed alloy and their feasibility in industrial process.