Effect of trace boron on grain refinement of commercially pure aluminum by Al-5Ti-1B
(1. Shanghai Key Lab of Advanced High-temperature Materials and Precision Forming and State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China;
2. National Engineering Research Center of Light Alloy Net Forming, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China;
3. Shenzhen Almate Inc., Shenzhen 518102, China;
4. School of Engineering and Computer Science, University of Hull, Hull, HU6 7RX, UK)
2. National Engineering Research Center of Light Alloy Net Forming, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China;
3. Shenzhen Almate Inc., Shenzhen 518102, China;
4. School of Engineering and Computer Science, University of Hull, Hull, HU6 7RX, UK)
Abstract: The effect of boron content on grain refinement of commercially pure aluminum by Al-5Ti-1B was quantitatively assessed. When the boron content is less than 0.03 wt.%, the refining performance of Al-5Ti-1B gradually is weakened as the boron content increases, which is attributed to the reaction of boron with the Al3Ti interlayer on TiB2 and the consumption of solute Ti. On the contrary, when the boron content exceeds 0.03 wt.%, the refining performance of Al-5Ti-1B gradually recovers with increasing boron content, which is related to the formation of primary AlB2 particles that provide additional nucleant substrates.
Key words: aluminum alloy casting; Al-5Ti-1B; grain refinement; boron treatment; nucleation