Aluminum alloy clad material
An Al—Si—Mg—Bi-based brazing material containing Si: 6.0% to 14.0%, Fe: 0.05% to 0.3%, Mg: 0.02% to 1.5%, Bi: 0.05% to 0.25%, Sr: 0.0001% to 0.1%, and a balance of Al and inevitable impurities, and satisfies (Bi+Mg)×Sr≤0.1, is disposed on both surfaces of a core material, Mg—Bi-based compounds of the brazing material with a diameter of 0.1 μm or more and less than 5.0 μm in terms of equivalent circle diameter are more than 20 in number in 10,000 μm 2 and the Mg—Bi-based compounds with diameter of 5.0 μm or more are less than 2 in number in 10,000 μm 2 , the core material contains Mn: 0.8% to 1.8%, Si: 0.01% to 1.0%, Fe: 0.1% to 0.5%, and a balance of Al and inevitable impurities, and a cathode current density of a brazing material layer after a brazing heat treatment is 0.1 mA/cm 2 or less.
1. An aluminum alloy clad material comprising:
an Al—Si—Mg—Bi brazing material disposed on both surfaces of a core material wherein the Al—Si—Mg—B brazing material comprises, by mass %, from 6.0% to 14.0% of Si, from 0.05% to 0.3% of Fe, from 0.02% to 1.5% of Mg, from 0.05% to 0.25% of Bi, from 0.0001% to 0.1% of Sr, and a balance consisting of Al and inevitable impurities, and satisfies a relationship of (Bi+Mg)×Sr≤0.1 in amounts of elements by mass %,
wherein the Al—Si—Mg—Bi brazing material comprises more than 20 in number per 10,000-μm 2 visual field of Mg—Bi compounds having a diameter of from 0.1 μm to less than 5.0 μm in terms of equivalent circle diameter and less than 2 in number per 10,000-μm 2 visual field of the Mg—Bi compounds having a diameter of 5.0 μm or more, when observed in a surface layer plane direction before brazing, and
the core material comprises, by mass %, from 0.8% to 1.8% of Mn, from 0.01% to 1.0% of Si, from 0.1% to 0.5% of Fe, and a balance consisting of Al and inevitable impurities, and a cathode current density of a brazing material layer measured at room temperature in a 5% NaCl solution at a pH of 3 after a brazing heat treatment is 0.1 mA/cm 2 or less.
2. The aluminum alloy clad material according to claim 1 , wherein the core material further comprises, by mass %, from 0.005% to 0.3% of Cu.
3. The aluminum alloy clad material according to claim 1 , wherein the core material further comprises, by mass %, from 0.1% to 0.7% of Mg.
4. The aluminum alloy clad material according to claim 2 , wherein the core material further comprises, by mass %, from 0.1% to 0.7% of Mg.
5. The aluminum alloy clad material according to claim 1 , wherein the core material further comprises, by mass %, from 0.2% to 1.6% of Zn.
6. The aluminum alloy clad material according to claim 2 , wherein the core material further comprises, by mass %, from 0.2% to 1.6% of Zn.
7. The aluminum alloy clad material according to claim 3 , wherein the core material further comprises, by mass %, from 0.2% to 1.6% of Zn.
8. The aluminum alloy clad material according to claim 4 , wherein the core material further contains, by mass %, from 0.2% to 1.6% of Zn.
9. The aluminum alloy clad material according to claim 1 , wherein the brazing material further comprises, by mass %, from 0.05% to 0.3% of Mn.
10. The aluminum alloy clad material according to claim 2 , wherein the brazing material further comprises, by mass %, from 0.05% to 0.3% of Mn.
11. The aluminum alloy clad material according to claim 3 , wherein the brazing material further comprises, by mass %, from 0.05% to 0.3% of Mn.
12. The aluminum alloy clad material according to claim 4 , wherein the brazing material further comprises, by mass %, from 0.05% to 0.3% of Mn.
13. The aluminum alloy clad material according to claim 5 , wherein the brazing material further comprises, by mass %, from 0.05% to 0.3% of Mn.
14. The aluminum alloy clad material according to claim 6 , wherein the brazing material further comprises, by mass %, from 0.05% to 0.3% of Mn.
15. The aluminum alloy clad material according to claim 7 , wherein the brazing material further comprises, by mass %, from 0.05% to 0.3% of Mn.
16. The aluminum alloy clad material according to claim 8 , wherein the brazing material further comprises, by mass %, from 0.05% to 0.3% of Mn.
17. The aluminum alloy clad material according to claim 1 , wherein a concentration of Mg on a surface of the brazing material at a braze melting temperature is from 0.15% to 1.0%.
18. The aluminum alloy clad material according to claim 3 , wherein a concentration of Mg on a surface of the brazing material at a braze melting temperature is from 0.15% to 1.0%.
19. The aluminum alloy clad material according to claim 5 , wherein a concentration of Mg on a surface of the brazing material at a braze melting temperature is from 0.15% to 1.0%.
20. The aluminum alloy clad material according to claim 7 , wherein a concentration of Mg on a surface of the brazing material at a braze melting temperature is from 0.15% to 1.0%.
21. The aluminum alloy clad material according to claim 1 , wherein the Al—Si—Mg—B brazing material comprises, by mass %, from 0.03% to 1.5% of Mg.
22. The aluminum alloy clad material according to claim 1 , wherein the Al—Si—Mg—B brazing material comprises, by mass %, from 0.05% to 1.5% of Mg.
23. The aluminum alloy clad material according to claim 1 , wherein the Al—Si—Mg—B brazing material comprises, by mass %, from 0.1% to 1.5% of Mg.