Mechanical Treatments 
      Whilst  mechanical treatments often remove the bulk of surface damage, they often add  further complications and hide underlying problems. 
      Metals are  crystalline structures and when looking closely at such surfaces, the crystal  structure should be easily seen. Once again, going back to how the original  material is formed, this group of materials easily plasticize at 500ºC, allowing the upper layer to be  pushed over damaged sites and for inclusions, debris and contaminates to be  trapped within the upper surface layer 
        
        
      Mechanical  treatments can also induce heat that far exceeds the phase changes of the  material, taking them into the molten stages at local sites and enables cold  quenching to take place with the material behind the local sites that remains  within the stable phase, leading to local phase changes to take place. 
      Below details a typical phase change and oxide  generation with applying various mechanical treatments 
        
        
        
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