Erosion resistance of a laser surface treated Ti6Al4V titanium alloy

Abstract

High hardness values associated with a suitable ductility, good elastic properties and high thermic conductivities seem to be required conditions to satisfactoryly withstand impacts and solid particle erosion.To this end, different surface treatment laser processes were developed on a Ti-6Al-4V Titanium alloy: - Laser nitriding was accomplished at solid state under a nitrogen flow by reactive formation of a TiN nitride layer (2-3 μm thick). - Boronitrided layers (consisting predominantly of borides TiB and nitrides TiN) were formed by laser melting of a boran nitride predeposit. Depending on the dilution rate, dense coatings or thicker alloying zones or even only precipitation at titanium grains boundaries were obtained. - Injection of hard diborides particules (TiB2) to obtain dispersoid structures. Topographic features and damage mechanisms associated with erosive particle impact craters are studied when erosion rates are evaluated by measuring the weight loss produced by the erosion test.High hardness values associated with a suitable ductility, good elastic properties and high thermic conductivities seem to be required conditions to satisfactoryly withstand impacts and solid particle erosion.To this end, different surface treatment laser processes were developed on a Ti-6Al-4V Titanium alloy: - Laser nitriding was accomplished at solid state under a nitrogen flow by reactive formation of a TiN nitride layer (2-3 μm thick). - Boronitrided layers (consisting predominantly of borides TiB and nitrides TiN) were formed by laser melting of a boran nitride predeposit. Depending on the dilution rate, dense coatings or thicker alloying zones or even only precipitation at titanium grains boundaries were obtained. - Injection of hard diborides particules (TiB2) to obtain dispersoid structures. Topographic features and damage mechanisms associated with erosive particle impact craters are studied when erosion rates are evaluated by measuring the weight loss produced by the erosion test.