Wrought alloys contain low percentages of elements; that is, alloying elements total less than about 4 pct. Casting alloys contain the same elements as wrought, but in greater amounts; for example, the silicon content in cast alloys can range up to 22 pct.

Most aluminum casting alloys undergo a catastrophic loss of mechanical properties (tensile, impact, shear strength etc.) in the temperature range from 520 to 590 degrees C. In comparison, wrought aluminum alloys retain their mechanical properties and remain ductile within this temperature range.

Quotes from the report of R. D. Brown, Jr., F. Ambrose, and D. Montagna "Separation of Cast and Wrought Aluminum Alloys by Thermomechanical Processing"

You can also find information about cast and wrought alloy designation systems and general characteristics of each alloy family in the book of J.R. Davis "Corrosion of Aluminum and Aluminum Alloys" (I attached the link). Hope this helps.

https://books.google.com/books?id=iEeiQEeLOmYC&pg=PA10&lpg=PA10&dq=cast+and+wrought+aluminum+alloys+criteria+to+divide&source=bl&ots=EJl5TYY1Qd&sig=hPdYns0iUrN2WVVAEFZFiAsYTew&hl=com&sa=X&ei=qZpEVdTgNML5ygPGlYHIAg&redir_esc=y#v=onepage&q=cast%20and%20wrought%20aluminum%20alloys%20criteria%20to%20divide&f=false

forgeability will determine whether it will be a cast or wrought alloy

 I think that the differences between the two types of alloys (cast or wrougth) are a mix between requirements of part (for example more geometry detail: the part must be casting), the service conditions and the mechanical properties of each one.

I bend to same thinks as Daniel's and Olga's  comments

You can think about that . Aluminum alloys can be produce with casting or plastic deformation. Very few aluminum alloys can be produce like steel wrought and some studies about that (like SIMA) half solidification state phase metal can be produce with wrought. Therefore rolling, forging process temperature of aluminum doesn't like steel temp. in this reason  that is about principle of solidifications of aluminium alloys. 

Casting aluminium alloys in studies has given by some range of percentage elements but wrought alloys are giving with more specific data. This is about explain machinability. If you think about twin roll casting produce system, some aluminium alloys cannot produce with these system because alloys have to transform solid phase in very few times and some spesific alloys can be produce like wrought alloys.

 I tried to explain if i didn't i'm sorry :)

Dear Saman Mostafapoor,

Cast alloys have in general a composition close to an eutecticum, as the eutectic composition often denotes a  low melting temperature with a small viscosity enabling a good castability. The classical cast alloys, e.g. cast iron and silumin, form striking examples. Extrudability demands other processing properties and thus other compositions. So, processing of the alloys concerned determine to a large extent their characterization. See for a more elaborate discussion about the link between phase diagrams and alloy characteristics:

Materials Science in Design and Engineering

Pieter van Mourik, Jaap van Dam, Stephen J. Picken

VSSD, Delft NL, 468 p.

Dear Saman Mostafoor,

The correct link to Materials Science in Design and Engineering is:

http://www.vssd.nl/hlf/m017.htm

http://www.vssd.nl/hlf/m017.htm

The answer of P.Van Mourik is OK.

Thanks for your answers, I know one of them is good cast-ability, and it can be seen from solidification range and low solidification range usually happens in near eutectic compositions. But let's consider, for example, 7xx.x Al alloys. if the concentration of  Zn increases from 3 to 5 percent or more even to 20 percent, how to find out this alloy is good for cast or wrought?

Dear Saman Mostafapoor,

Your question is a little bit confusing. In the AA classification 7xx.x denotes a cast alloy with Sn as the main alloying element. The AA code 7xxx denotes a wrought alloy with Zn as the main alloying element. As a matter of fact the AA 7xxx series is based on the ternary system Al-Zn-Mg. Cast alloys with Zn as the main alloying element are denoted as AA 6xx.x. Increasing the Zn-content of alloys in the AA7xxx series may not alter the basic characteristics for the range of 3 - 5 wt% Zn. Such an alloy is basically a wrought alloy. A further increase until 20 wt % Zn can alter the characteristics of such a ternary alloy. The ternary system Al-Zn-Mg has to be studied in order to relate composition and castability. Note that for the application of such alloys the possibility of precipitation hardening in order to reach remarkable strength values is essential. As casting often implies compositional segregations and hence local variations of the strength properties to be obtained by heat treatment, casting does not seem the appropiate processing route for Al alloys with complicated compositions.

The Aluminum Association Inc. (1935) was responsible for the allocation and registration of aluminum alloys. Currently there are over 400 wrought aluminum alloys and over 200 aluminum alloys in the form of castings and ingots registered with the Aluminum Association. The wrought and cast aluminums have different systems of identification; the wrought having a 4-digit system, and the castings having a 3-digit and 1-decimal place system. This classification of aluminium alloys is further differentiated within the series based on heat treatable and non-heat treatable aluminium alloys. The 2xxx, 6xxx, and 7xxx series wrought aluminum alloys are heat treatable and the 4xxx series consist of both heat treatable and non-heat treatable alloys. The 2xx.x, 3xx.x, 4xx.x and 7xx.x series cast alloys are heat treatable. The Temper Designation System is an extension of the alloy numbering system and consists of a series of letters and numbers which follow the alloy designation number and are connected by a hyphen [c].

Dear Dhanashekar Manickam I think we are not in the same page. any way thanks for your attention.

Apart from every other comments made here, You can identify if an aluminium alloy is wrought or cast by looking at the identification systems: The wrought Al alloy uses the  International Aluminium alloy designation system (1000-7000 series), while the cast use an identification system that is made up of four-five digits with a decimal point inclusive, while the integer part take cognizance of the alloying elements present, the decimal part recognizes if it is in the cast or ingot form. Conversely, wrought alloys is almost usually in plate form. Hope this helps further

Thanks Dear Falarin and others

Sorry, I think i was not clear enough about my question.

My question includes the designing of an alloy. How should I choose the amounts of an alloying element which make it possible to create a wrought or cast alloy. I well know the classification rules of aluminum alloys. Let's consider you want to create a new alloy as a wrought alloy (a new 7xxx alloy for example). how many zinc can I add to the alloy while keep the wroughtablity of  the alloy? 2 or 4 or 8 or 15 or 20? what are the limitations to add alloying elements. Is there any identified protocol or it is completely experimental?