Search

Bosentan is a non-peptidic endothelin receptor antagonist used for the treatment of pulmonary artery hypertension (PAH), congestive heart failure and cardiovascular pathology.1,2 Bosentan monohydra...

High strength AA2219 aluminum alloys have gathered wide acceptance in aeronautic and aerospace applications mainly due to their excellent mechanical properties, high corrosion resistance and good weldability. However, these alloys have poor as welded joint strength. The loss of strength is due to melting and quick resolidification, which renders all the strengthening precipitates to dissolve. One way of improving strength is through the modification of weld microstructures. The refinement of fusion zone microstructure helps in improving the mechanical properties of weld metal. The present study has investigated the influence of Tibor additions on the structure and mechanical properties of AA2219 gas tungsten arc (GTA) weldments. Full penetration GTA welds were prepared using alternating current (AC). It was observed that grain size was decreased with increasing amounts of Tibor. The observed grain refinement was shown to result in an appreciable increase in fusion zone hardness.

The present study has investigated the influence of current pulsing on the structure and mechanical properties of Ti–6Al–4V tungsten inert gas (TIG) weldments. Autogenous full penetration bead on plate TIG welds were made with and without direct current pulsing. Microstructural observations and evaluation of hardness, tensile and fatigue properties of the weldments were made in different conditions: as welded and post-weld heat treatment (PWHT) conditions (PWHT was done at 700 and 900°C). Current pulsing resulted in slight refinement of prior β grains, leading to better tensile strength, ductility and fatigue lives of weldments in the as welded condition. In the case of weldments subjected to PWHTs, the pulsed weldments exhibited inferior fatigue lives compared with the unpulsed weldments. The PWHT done at 900°C resulted in inferior fatigue lives of weldments compared with that done at 700°C.