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Physi- cal and Chemical Properties of Aluminum and its Alloys

  • The density of pure aluminum is small, only 2.7fr/Cin3, compared with copper (8.9g/cm3) or iron (7.9g/cm3), only 1/3 of the two. The electrical attachment rate of aluminum is 2.61 pil • cm, which is ranked in silver (1.47^11 • cm), steel (1.58 jiH • cm) and gold (lOlpil . cm) in all low-resistivity metals. Four. These two alone are enough to show the unique position of aluminum in metallic materials. The physical properties of aluminum are shown in Table 2-2. Some important properties of aluminum alloys related to the brazing process are shown in Table 2-3. The characteristics of each alloy listed in Table 2-3 are sorted by American Alloy No. AA, and the GB grades with the alloy composition are listed as much as possible for reference.

Table 2-2 Physical properties of aluminum

14 # ( Still purity aluminum 1 IP pass purity aluminum
99.9%%) (99.5%)
Atomic number 13
Relative atomic quality 26.97
20 弋 lattice constant (heart-centered cubic lattice) / nm 0.40413 0.404
Density (20 especially) / (g/on3) 2.689 2.70
Density (70 (rC) / (g / Cm3) 2.373
Melting point / T 660.2 -655
Boiling point / especially 2060
Linear expansion coefficient (20 ~ 100T) / io_6<c -1 24.58 23.5
Linear expansion coefficient (100 ~ 3001) / \0’6X 25.45 25.6
Solidification shrinkage (volume) (%) 6.6
Specific heat 100t:/(J/g) 0.9305 0.9601
Latent latent heat / (J / g) 395.4 388.7
Heat of combustion / (J / g) 30.88 30.93
Thermal conductivity (2 2.215
Conductivity (for standard copper) (%) 64.94 60(annealed material)
Specific impedance 20*^/^ • cm 2.6548 2.922
Temperature coefficient of impedance / (10_3/*0 4.2 4.0
Reflectance A = 250nm ( % ) .一 87
Reflectance A = 500nm ( % ) 90
Reflectance A = 2000nm (%) .— 97

Table 2-3 Properties of some important aluminum alloys concerning with brazing and soldering

Alloy code Characteristic alloying element

(Quality score, %)

Solid phase line

/X

Tensile strength / MPa Yield strength / MPa Elongation(%) Corrosion resistance status
American AA China GB new (old) Brazing Soldering
1050 1050A(I3) 99.5A1 646—657 76 28 A A A 0
1060 1060(L2) 99.6A1 646—657 69 28 43 A A A 0
1100 1100(L5-1) 99.1A1-0.12Cu 643—657 90 34 35 A A A 0
1145 1145 99.45AU0.3Si 646—657 75 34 40 A A A 0
1199 (L03) 99.99A1 660—660 45 10 50 A A A 0
1350 1350 99.50A1 646—657 83 28 23 A A A 0
1460 2.2U-3. OCu-0.05Mg-0. IZr-O. ISc 440 11 B C resi
2011 2011 5.5Cu-0.4Pb-0.4Bi-0.3Zn 535(m)—541 — 638 380 295 15 D D C T3
2014 2A14(LD10) 4.4Cu-0.8Si4).8Mn-0.5Mg 507—638 185 97 21 D C 0
2017 2RI1(LY8) 4.2Cu-0.6Mg-0.6Mn^).5Si 513—641 183 70 22 D NA 0
2018 2A90(LD9) 4.0Cu-2.0Ni-0.8Si-().6Mg 507—^38 B
2020 4.5Cu-1.5Li-0.5Mn-0.2Cd 210 145 19 0 0
2024 2A12(LY12) 4.4Cu-l. 5Mg-0. 6Mn 502—638 185 76 20 D C 0
2036 2.6Cu-0.45Mg-0.25Mn 510(m)—554— 649 340 195 24 T4
2090 2.7Cu-2.2Li-0.12Zr-0.25Mg 560-650 213 193 11 B D 0
2091 2. lCu-2.0U-1.0Mg-0. lOZr 560—670 B D
2117 2A01(LY1) 2.6Cu-0.8Si-0.3Mg 555—650 160 60 24 D 0
2124 4.4Cu-1.5Mg-0.6Mn 502—638 490 440 9.4 C D T851
2218 4.0Cu-2.0Ni-1.5Mg 504(m)—532— 635 405 305 13 D C T61
2219 2B16

(LY16-1)

6.3Cu-0.3Mn-0. 18Zr-0. 10V-0.06Ti 543—M3 170 76 18 D 0
2618 2A70(LD7) 2. 3Cu-l. 6Mg-l. IFe-l. 0Ni-0. 18Si- 0.07Ti 502(m)—549— 638 440 370 10 D D T61
3003 3003 1.2Mn-0.12Cu 643-HS54 110 42 30 A A A 0
3004 3004 1.2Mn-1.0Mg 629—654 180 69 20 A B B 0
3005 3005 1.3Mn-0.6Si-0.4Mg-0.3Cu 130 45 10 A 0
3010 0.5Mn-0.2Cr
3105 3105 0.55Mn-0.50Mg 638—657 115 55 24 A B B 0
4002 4.0Si-1.1Cd-0. lMg 575—638 A D NA
  • The solidus temperature listed in Table 2-3 is an insurmountable limit for brazing operations, otherwise the alloy will overfire. In fact, due to the heterogeneity of the alloy grade and the manufacturer’s product, the brazing temperature is always at least lower than the solidus to ensure safety. However, the alloy in the table exhibits a eutectic temperature (e), and the initial melting temperature (m) after homogenization solution treatment is relatively high, so the actual brazing temperature can be higher than (e), but Can be approximated (m>. In addition, often also consider the mechanical properties of the workpiece, so the choice of nailing temperature should also refer to the heat treatment specifications of the alloy. The thermal properties of aluminum alloys are generally close, knowing the approximate value without detailed For example, the specific heat capacity of aluminum alloy is about 0.9丨/(8.<0(20弋); the coefficient of linear expansion is about 23 X 10 6弋1 (20 ~ 100^), which is better than pure Cul7.4xlO-6lC-\ H62 brass SOJxlOdT』-1, pure Nil6. 7 x 10_6<€, steel 12. 6 x are larger;
  • aluminum alloy thermal conductivity is 1.25 ~ 2.5W / (cm. t). Aluminum and most aluminum The density of the alloy is between (2_7 ± 0.1 l) g / cm3, which contains different amounts of heavy metals (Cu, Zn, etc.) and light metals (Mg, etc.) and the density is slightly undulating. A few Al-Li-Mg alloys The relative density is as small as about 2.5^/cm3. The ratio of pure conductivity to annealed copper is about 60% of the latter (called specific conductivity), and the average aluminum alloy is about 50%. The specific conductivity of aluminum alloys with higher Mg content is lower, for example, 5A02 (LF2), 5A05 (I.F5) and other anti-rust aluminum series, but its specific conductivity is not less than 30%. Copper (H62) 27%, pure Ni24%, low carbon steel 14% and ratio are still high electrical conductivity. The mechanical properties of aluminum alloys have a great change, as listed in Table 2-3, the annealing softening is selected as much as possible. State data to provide a reference for the worst possible conditions after Vacuum brazing furnace.
  • In China’s new number of deformed aluminum alloys, most of them are not compatible with AA except for the AA number and alloy composition. This can be seen from Table 2-3. Due to the alternation of the old and new numbers, especially the old number has not yet been able to withdraw from people’s thoughts, it is necessary to have a description of the old and new numbers and the corresponding components. Table 24 lists the corresponding data. Because the modified aluminum alloy of GB grade lacks the data related to Xuanzheng, if necessary, the reader can judge the brazing performance according to the alloys with similar AA main components in Table 24屮GB and Table 2-3.
  • Because of the coarse grain size and the loose structure, the cast-peel alloy is inferior to the deformed aluminum material. In particular, cast aluminum alloys containing Si or containing a relatively large amount of Mg are more difficult to be wetted by the molten solder. Only a few grades of cast aluminum alloys can be considered for brazing if necessary. For example, ZL201 (Al(:»5Mn) and ZL203 (A1-Cu4) have better pinning effect, and secondly, ZL105 (AlSi5CulMg) can be considered. For the relevant parameters, see the four data at the end of Table 2-3.