Effect of laser power on the microstructure and mechanical properties of laser deposited titanium aluminide composite

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ABSTRACT

In this work, titanium aluminide alloy have been fabricated via the laser deposition technique. The effect of some selected deposition parameters on the microstructure and mechanical properties of produced deposits were studied. The relationship between the laser power, and the microhardness of deposited samples on laser preheated substrate showed an incremental change in laser power from 200 to 600 W. This led to an overall decrease in microhardness of deposited samples from 426 to 373 HV. Sample deposited at 500 W gave the lowest Icorr of 1.8 x 10^-8 and the highest Ecorr of -0.138 V. It is evident from the nanoindentation results that indentation modulus and stiffness of sample deposited at 600 W laser power had a lower value compared with 400 W laser power. However, the modulus of both samples fell within titanium alloy modulus range between 105-120 GPa. The microstructures of the deposits are mainly characterized with γ-TiAl and α₂-Ti₃Al phases and an improved hardness property almost two times higher than that of commercially pure titanium were achieved.  It was concluded that changes in the laser power directly causes changes in the microstructure, hardness, stiffness, modulus of elasticity and corrosion resistance of the deposits.

KEYWORDS:

• Additive manufacturing
• laser power
• laser metal deposition
• deposition parameter
• titanium aluminide

Acknowledgments

The authors acknowledged The National Laser Centre, Council for Scientific and Industrial Research, Pretoria, South Africa, for the support provided to utilize their laser deposition equipment for this study.

Disclosure statement

No potential conflict of interest was reported by the author(s).