Mechanical properties of additive manufactured titanium (Ti-6Al-4V) blocks deposited by a solid-state laser and wire

In this paper, the mechanical properties and chemical composition of additive manufactured Ti-6Al-4V blocks are investigated and compared to plate material and aerospace specifications. Blocks (seven beads wide, seven layers high, 165 mm long) were deposited using a 3.5 kW Nd:YAG laser and Ti-6Al-4V wire. Two different sets of process parameters are used and three different conditions (as-built, 600 degrees C/4 h, 1200 degrees C/2 h) of the deposit are investigated. The particular impurity levels of the blocks are considerably below those tolerated according to aerospace material specifications (AMS 4911L). Static tensile samples are extracted from the blocks in the deposition direction and punch samples are extracted in the building direction. The experiments show that as-deposited Ti-6Al-4V can achieve strength and ductility properties that fulfill aerospace specifications of the wrought Ti-6Al-4V material (AMS 4928). The 600 degrees C/4 h heat treatment leads to a significantly higher strength in the deposition direction, but can also decrease ductility. The 1200 degrees C/2 h treatment tends to decrease the alloy's strength. (C) 2011 Elsevier Ltd. All rights reserved.