AT160440B - Heat-treatable magnesium alloy with aluminum and bismuth content. - Google Patents

Description

  

   <Desc / Clms Page number 1>
 



  Heat-treatable magnesium alloy with aluminum and bismuth content.



   The present invention relates to a further embodiment of the castable magnesium alloys of high strength and containing aluminum and bismuth protected by patent no. 158393. According to the parent patent, the alloys contain 8-14% aluminum and 4-14% bismuth, the remainder being magnesium.



   The magnesium alloys according to the invention have a content of 0.05 to 8% aluminum and more than 2 to 14% bismuth. Surprisingly, it has been shown that the limitations given in the parent patent for the alloy components aluminum and bismuth can be changed in the manner that characterizes the invention, ie. This means that an aluminum content lower than 8% is permissible, while the bismuth content can also be reduced below 4%, but should always be more than 2%. As a result of these measures, magnesium alloys are obtained according to the invention which have similarly high mechanical properties and also useful corrosion resistance, as is the case with the magnesium alloys according to the parent patent.

   The alloys according to the invention are particularly suitable as materials in vehicle and aircraft construction, where, in addition to low weight, high strength is important.



   Aluminum and bismuth-containing magnesium alloys with bismuth contents of up to 2% are already known, but these have not been introduced in practice because of their low strength. These known magnesium alloys were content with a bismuth content of at most 2%, since it was assumed that a further increase in the bismuth content would not result in any improvement in the alloy.



   The following test results clearly show that this assumption was wrong. In this case, two known and three bismuth-containing magnesium alloys corresponding to the invention were pressed and then subjected to cold deformation (drawn), the tensile strength and elongation were determined, while as a measure of the corrosion resistance, the number of Hydrochloric acid evolved cubic centimeters of hydrogen were used.



   Composition of the alloys:
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<tb>
<tb> aluminum <SEP> bismuth <SEP> magnesium
<tb> 1. <SEP> 3% <SEP> 0, <SEP> 5% <SEP> rest
<tb> 2. <SEP> 2% <SEP> 1 <SEP>% <SEP> rest
<tb> 3. <SEP> 5% <SEP> 8 <SEP>% <SEP> rest
<tb> 4. <SEP> 8% <SEP> 5 <SEP>% <SEP> rest
<tb> 5. <SEP> 4% <SEP> 12 <SEP>% <SEP> rest
<tb>
 

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 EMI2.1
 
 EMI2.2
 
<tb>
<tb> alloy <SEP> tensile strength <SEP> elongation at break <SEP> hydrogen
<tb> kg / mm2 <SEP> 010% <SEP> cm3
<tb> 1 <SEP> 32 <SEP> 7 <SEP> 60
<tb> 2 <SEP> 32, <SEP> 5 <SEP> 5 <SEP> 50
<tb> 3 <SEP> 44.5 <SEP> 4 <SEP> 30
<tb> 4 <SEP> 43.5 <SEP> 5 <SEP> 30
<tb> 5 <SEP> 47.0 <SEP> 3 <SEP> 40
<tb>
 
These comparative tests clearly show that increasing the bismuth content above the known amount of 2% results in a significant improvement in the technological properties.

   With the new alloys, significantly increased mechanical properties are obtained, while the corrosion resistance is also improved in an acceptable manner.



   Magnesium alloys which have the following composition are to be mentioned as further advantageous exemplary embodiments of the invention:
1.6.5% aluminum, 5% bismuth, balance magnesium;
2.8% aluminum, 4% bismuth, remainder magnesium;
3.1, 5% aluminum, 12% bismuth, the rest magnesium.



   The alloys according to the invention can be used as cast and wrought alloys.



  Usual additives. can be added to the magnesium alloys according to the present invention in known amounts. So it is e.g. B. known to add calcium to improve the castability, manganese to increase the corrosion resistance and one or more of the metals of the iron group or silicon to increase the high temperature strength and the yield point. The additions are made in contents of about 0.1 to 2%. This does not change the character of the alloys according to the invention.

 

Claims (1)

PATENT CLAIM: Heat-treatable magnesium alloy with aluminum and bismuth content according to patent no. 158393, which may contain other additives common to magnesium alloys, such as. B. manganese, calcium, silicon, one or more of the metals of the iron group, characterized by a content of 0.05 to 8% aluminum and more than 2 to 14% bismuth, the remainder being magnesium.