Microstructure of Ti-45Al-5Nb after Cathodic Charging

2010 ◽  
Vol 95 ◽  
pp. 87-90
Author(s):  
E. Barel ◽  
Guy Ben-Hamu ◽  
D. Eliezer

Gamma titanium aluminide material, cast Ti–45Al–5Nb (at.%), was electrochemically precharged with hydrogen in the cathodic charging mode at a current density of 50 mA/cm2 for times ranging from 6 to 48 h. XRD and microstructure investigations by means of electronic microscopy were used for analyzed the influence of hydrogen on the microstructure.

Author(s):  
Fritz Klocke ◽  
Tim Herrig ◽  
Markus Zeis ◽  
Andreas Klink

Additive manufacturing technologies are becoming more and more important for the implementation of efficient process chains. Due to the possibility of a near net shape, manufacturing time for finish-machining can significantly be reduced. Especially for conventionally hard to machine materials like gamma titanium aluminides (γ-TiAl), this manufacturing process is very attractive. Nevertheless, for most applications, a rework of these generative components is necessary. Independently of the mechanical material properties, electrochemical machining is one promising technology of machining these materials. Major advantages of electrochemical machining are its process-specific characteristics of high material removal rates in combination with almost no tool wear. But electrochemical machining results are highly dependent on the microstructure of the material regarding the surface roughness. Therefore, this article deals with research on electrochemical machining of electron beam melted γ-TiAl TNB-V5 compared to a casted form of this alloy. The difference between the specific removal rates as a function of current density is investigated using electrolytes based on sodium nitrate and sodium chloride. Moreover, the dissolving behavior of the electron beam melted and casted structure is analyzed by potentiostatic polarization curves. The surface roughness is heavily dependent on a homogeneous dissolution behavior of the microstructure. Thus, the mean roughness as a function of current density is investigated as well as rim zone analyses of the different structures.


Author(s):  
H. Ali Razavi ◽  
Steven Danyluk ◽  
Thomas R. Kurfess

This paper explores the limitations of a previously reported indentation model that correlated the depth of plastic deformation and the normal component of the grinding force. The indentation model for grinding is studied using force control grinding of gamma titanium aluminide (TiAl-γ). Reciprocating surface grinding is carried out for a range of normal force 15–90 N, a cutting depth of 20–40 μm and removal rate of 1–9 mm3/sec using diamond, cubic boron nitride (CBN) and aluminum oxide (Al2O3) abrasives. The experimental data show that the indentation model for grinding is a valid approximation when the normal component of grinding force exceeds some value that is abrasive dependent.


1998 ◽  
Vol 552 ◽  
Author(s):  
R. Raban ◽  
L. L. ◽  
T. M.

ABSTRACTPlates of three gamma titanium aluminide alloys have been investment cast with a wide variety of casting conditions designed to influence cooling rates. These alloys include Ti-48Al-2Cr-2Nb, Ti- 47Al-2Cr-2Nb+0.5at%B and Ti-45Al-2Cr-2Nb+0.9at%B. Cooling rates have been estimated with the use of thermal data from casting experiments, along with the UES ProCAST simulation package. Variations in cooling rate significantly influenced the microstructure and tensile properties of all three alloys.


Author(s):  
A. Seidel ◽  
T. Maiwald ◽  
T. Finaske ◽  
S. Polenz ◽  
S. Saha ◽  
...  

2012 ◽  
pp. 278-294
Author(s):  
Mauro Filippini ◽  
Stefano Beretta ◽  
Luca Patriarca ◽  
Giuseppe Pasquero ◽  
Silvia Sabbadini

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