Elevated Temperature Characterization of Electron Beam Deposited Ti-6Al-4V and Ti-8Al-1Er

Electron beam freeform fabrication is a method to build structural metallic parts from CAD files rather than through the conventional method of machining parts from large plates.  This process could result in significant cost savings and the ability to make use of alloys that are not suited to production via ingot metallurgy processes.  Ti-8Al-1Er is a dispersion strengthened titanium alloy not amenable to ingot metallurgy production methods.

  In this work, the room temperature tensile, elevated temperature tensile, and creep properties of electron beam deposited Ti-6Al-4V and Ti-8Al-1Er were measured and compared to those of laser beam deposited Ti-8Al-1Er and some widely used wrought titanium alloys.  Elevated temperature tensile properties were measured between 93^o and 538^o C (200^o to 1000^o F).  Creep tests were performed between 425^o and 455^o C (797^o to 851^o F).  It was found that the properties of the electron beam deposited products are comparable to those of wrought forms.  The elevated temperature strengths of Ti-8Al-1Er are comparable to those of Ti-6Al-4V in percentage of room temperature strength retained at temperature.  Based on a Larson-Miller analysis of the creep test data, the creep resistance of Ti-8Al-1Er is superior to that of Ti-6Al-4V, but inferior to that of laser beam deposited Ti-8Al-1Er.  The inter-alloy improvement in creep resistance increases with decreasing temperature and stress. 

 

This work indicates that electron beam deposited titanium products may hold promise for elevated temperature applications.  However, further work is needed to develop a commercially feasible product