Abstract
The effect of laser trimming on the tensile strength and fatigue resistance of titanium-6% aluminum-4% vanadium specimens was investigated. Due to the nature of laser processing, the microstructure of the titanium alloy was altered in an area local to the cut known as the heat affected zone (HAZ). Experimental cutting was conducted in order to optimize laser process parameters to minimize the HAZ. It was discovered that the adhesion of small resolidified droplets (dross) to the bottom of the cut caused the greatest increase in the HAZ. Test specimens of two thicknesses, namely 0.020' and 0. 1 25', were cut by three laser sheet metal cutting laboratories at parameter values determined to be the optimum by each respective laboratory. Extreme effort was taken to meaningfully compare the results of tensile strength and fatigue life data, using statistical techniques, to that of mechanically machined and polished specimens as a material reference. The ultimate tensile strength (UTS) of machined specimens was higher than the laser cut specimens for the 0. 1 25' thick specimens while no difference could be detected for the 0.020' thick specimens. The fatigue life of one particular set of 0. 1 25" thick specimens appeared to have the same fatigue life of the machined samples. All of the 0.020" thick laser cut fatigue specimens had a lower fatigue life than the machined specimens.
Whitesel, Dean Adam (1994). The effects of laser trimming on the tensile strength and fatigue resistance properties of titanium - 6Al-4V. Master's thesis, Texas A&M University. Available electronically from
https : / /hdl .handle .net /1969 .1 /ETD -TAMU -1994 -THESIS -W5947.