Mechanical Testing of single crystals

[MechatroPro]

i'm looking for mechanical test methods and testing equipments for single crystal materials including tensile/compression tests,fatigue,creep tests,... (for Single crystal superalloys which are used in gas turbines)
any standards,codes,test methodes?

 

[UconnMaterials]

MechatroPro,

I'm not aware of any specific ASTM or AMS specs for testing single crystals. Most companies (ie GE or Pratt & Whitney) have their own internal specs for testing these materials. In practice the testing is no different than polycrystalline materials, but the results are going to depend on the orientation of the crystal with respect to the tensile axis.

I'm sure you are aware of the anisotropy of the mechanical properties of single crystal materials. Single crystal materials are grown specifically so that the load is along a specific crystalline axis. The testing is no different than a polycrystalline material except you need to know what crystalline axis to apply your load.

Best Regards

 

[MechatroPro]

Yes this is true, but because SC alloys are used in high temrature conditions,they need special test methods.

 

[UconnMaterials]

MechatroPro,

Polycrystalline and directionally solidified materials are also used (although not preferably) at high temperatures. Therefore, high temperature mechanical tests are still done on polycrystalline materials. For example, I believe ASTM E139 (for creep testing) pertains to both polycrystalline and single crystal materials.

Best Regards