Investigation of Porosity Changes in Cast Ti6Al4V Rods After Hot Isostatic Pressing

The porosities of cast Ti6Al4V rods were investigated nondestructively using x-ray microcomputed tomography (microCT) before and after HIP. This allowed the visualization and quantification of porosity changes in the same samples, which indicate excellent pore closure for large pores. This is the first reported application of x-ray microCT for direct analysis of investment casting porosity before and after HIP. The method shows promise for further investigations using delayed HIP treatments or monitoring of pore closure at further varying HIP cycle settings. The nondestructive nature of the analysis has resulted in the interesting observation of small subsurface pores (<250 μm) unaffected by hot isostatic pressing in two of the samples.

[1]  Anton Plessis,et al.  Simple and fast porosity analysis of concrete using X-ray computed tomography , 2016 .

[2]  N. Yoshikawa,et al.  X-Ray CT Inspection for Porosities and Its Effect on Fatigue of Die Cast Aluminium Alloy * , 2008 .

[3]  Helen V. Atkinson,et al.  Fundamental aspects of hot isostatic pressing: An overview , 2000 .

[4]  R. Saha,et al.  Casting of Titanium and its Alloys , 1986 .

[5]  J. D. Cotton,et al.  Titanium investiment casting defects: A metallographic overview , 2006 .

[6]  W. Kalender X-ray computed tomography , 2006, Physics in medicine and biology.

[7]  Anton du Plessis,et al.  X-ray computed tomography of a titanium aerospace investment casting , 2015 .

[8]  G. Michael,et al.  X-ray computed tomography , 2001 .

[9]  P. Withers,et al.  Quantitative X-ray tomography , 2014 .

[10]  G. Nicoletto,et al.  Characterization of microshrinkage casting defects of Al–Si alloys by X-ray computed tomography and metallography , 2012 .

[11]  B. Fedelich,et al.  Pore annihilation in a single-crystal nickel-base superalloy during hot isostatic pressing: Experiment and modelling , 2013 .

[12]  C. Zou,et al.  Effect of Micro-porosities on Fatigue Behavior in Aluminum Die Castings by 3D X-ray Tomography Inspection , 2014 .

[13]  Iain Todd,et al.  XCT analysis of the influence of melt strategies on defect population in Ti?6Al?4V components manufactured by Selective Electron Beam Melting , 2015 .

[14]  Gianni Nicoletto,et al.  X-ray computed tomography vs. metallography for pore sizing and fatigue of cast Al-alloys , 2010 .