Aluminum Squeeze Casting 3

[semisolid]

I am interested in getting physical properties (UTS, YTS, Elong, Hardness and 10**7 cycles fatigue value. I am interested in A356, 357 and 355 alloy values at T5 and T6 heat treatment. Thanks

 

[TVP]

By what casting process would these alloys be processed? Low pressure permanent mold? High pressure die cast? Squeeze casting? I can give you some general numbers based on the casting process, but mechanical properties, especially fatigue strength, are HIGHLY dependent on the quality of the castings, i.e., what levels of porosity (both shrinkage and macro gas porosity) are present, how fine is the grain size, is the eutectic modified properly, are there deleterious oxides and intermetallics present, etc.

Some good references for you to check out for this type of information include:

ASM HANDBOOK Volume 2 Properties and Selection: Nonferrous Alloys and Special-Purpose Materials

ASM HANDBOOK Volume 19 Fatigue and Fracture

ASM HANDBOOK Volume 15 Casting

Atlas of Fatigue Curves, edited by H. E. Boyer

Fatigue Data Book: Light Structural Alloys

ASM SPECIALTY HANDBOOK: Aluminum and Aluminum Alloys (compendium of info in Volumes 2-21 of ASM HANDBOOK series)

Properties of Aluminum Alloys: Tensile, Creep, and Fatigue Data at High and Low Temperatures

Aluminum: Properties and Physical Metallurgy


All of these publications can be obtained through ASM International at

http:///

http://www.asminternational.org

 

[semisolid]

The process is high pressure squeeze casting (20,000+ psi), and the idea is to fill a closed steel cavity (part shape) with molten AL at approx. 1300 deg. F at a slow ingate velocity (2"/sec). The object of the process is to fill the cavity without turbulence that would normally entrap atmosphere or mold gases, then feed the shrinkage at high pressure--the resulting part is relatively free of porosity. The properties of T-5 casting are not readily available. Please Help!!

 

[TVP]

semisolid,

In addition to the references I mentioned before, the following SAE Technical Papers all have mechanical property information onn squeeze castings:

1999-01-0343
1999-01-0344
2000-01-1291
2001-01-0406

You can obtain these papers, as well as search for others at

http://www.sae.org.

The following is a summary of some of the mechanical property data for 356/A356 aluminum alloys in the T6 temper:

1999-01-0343: YIELD = 138-165 MPa (part with thick sections)
UTS = 255-276 MPa
ELONG = 13-17 %
Hardness = 45-55 HRB
Gas content < 35 x 10^-6 m^3/kg

YIELD = 220-240 MPa (part with thinner sections)
UTS = 290-310 MPa
ELONG = 10-14 %
Hardness = 48-63 HRB
Gas content < 30

Fatigue strength at 10^8 cycles: 110 MPa (unnotched) & 83 MPa (notched). Secondary Dendrite Arm Spacing (SDAS) of 12-20 micrometers.

1999-01-0344:
YIELD = 207 min (statistical) 231 (Weibull B1) 259 (Avg)
UTS = 276 min (statistical) 307 (Weibull B1) 329 (Avg)
ELONG = 8 min (stat) 8 (Weibull B1) 10.5 (Avg)
Fatigue @ 10^7: 70 (stat) 90 (Weibull B1) 103 (Avg)

Normal T6 treatment, 0.56 mm grain size, SDAS = 13 microns at 1mm below surf, 28 microns at 8 mm below surf.

The reason you cannot find any information on T5 treatment with these alloys, is because they do not respond very well to this type of treatment. A full solution heat treatment is required to fully dissolve all of the second-phase particles, etc. This results in maximum/optimum mechanical properties.

 

[semisolid]

Excellent info and references, thanks--semisolid