Particle erosion of die cast Al–14Si alloy and influence of friction stir process

Abstract

The current research aimed to explore the particle erosion of a die cast Al–14Si alloy, and how the particle erosion behaviour can be affected by modification of the microstructure via friction stir process. The results indicate that friction stirring of the alloy can annihilate the dendritic structure of primary α-Al, break the eutectic Si and β-Al₃(Fe,Mn)Si₂ particles lengthwise, cause the eutectic Si particles to become more rounded, and blend the second phase particles rather uniformly in the α-Al matrix. According to the SiO₂ particle erosion test at 15 and 90° impact angles, this microstructure modification can improve the erosion resistance by not only particle reinforcement of α-Al matrix but also suppressing the susceptibility of brittle cracking of the second phase particles.

Keywords:

• Particle erosion
• Die cast Al alloys
• Al–Si alloys
• Friction stir process
• Second phase particles
• Eutectic Si

The authors are gratefully acknowledge the financial support from the National Science Council of Taiwan (contract no. NSC 96-2628-E-006-008-MY3).