Growth Behavior of Pores and Hydrogen Desorption Behavior in Pure Aluminum and A 6 0 6 1 Aluminum Alloys

A n increase i n the volume fraction o f pores i n aluminum alloys causes a decrease i n the elongation and the strength o f alloys. T o improve the mechanical properties o f aluminum alloys, i t i s important t o understand the growth and shrinkage behavior o f pores. I n this study, w e analyzed the relationship between hydrogen desorption behavior and the growth/shrinking behavior o f pores i n A 6 0 6 1 alloys and pure aluminum using thermal desorption analysis and synchrotron radiation X-ray tomography. I n pure aluminum, the fine pores began t o annihilate a t temperatures above 500 degrees C and the relatively large pores coarsened. I n contrast, the pores shrank with increasing temperature i n A 6 0 6 1 alloy. The influence o f second-phase particles has been discussed a s a possible explanation for the difference i n the nature o f pores a t elevated temperatures i n pure aluminum and A 6 0 6 1 alloys. A s i n the A 6 0 6 1 alloy, much o f the hydrogen des o r b e d from the pores due t o heating i s released externally from the second phase particles o n the aluminum surface, resulting i n pore shrinkage due t o the internal pressure drop o f pores.