Influence of Microstructure on the Fatigue Behaviour of Blended Elemental Ti-6Al-4V Alloy Post-consolidated by Extrusion
The blended elemental route is currently the main way for obtaining cost-affordable titanium alloys.Via post-consolidation processes like hot isostatic pressing or thermomechanical processing,the material can achieve superior tensile properties with respect to ingot metallurgy.In this study,commercially pure Ti and 60Al-40V master alloy powders were blended,compacted and vacuum sintered achieving the Ti-6Al-4V alloy with high relative density(96.4%).The alloy was subsequently extruded in the β phase to obtain a fully-dense material(relative density of 99.9%),where the microstructure is still lamellar but the laths and the α grain-boundary are much finer.Additionally,a solution and aging treatment was performed to refine the microstructure of the extruded material through the decomposition of martensite.The tensile behaviour of the sintered,extruded and heat-treated Ti-6Al-4V alloy was studied,finding an overall improvement of the properties after extrusion and a considerable increase in strength without compromising ductility after heat treatment.The high cycle fatigue behaviour of the as-extruded alloy was also studied by means of axial testing.It was found that there is a strong dependence between the location of the initiation of failure of the alloy and its fatigue life,but the defects that initiated failure were facets and not pores.The fatigue life of the as-extruded alloy is comparable to that of other fully-dense powder metallurgy and ingot metallurgy Ti-6Al-4V alloys with lower interstitials content.These findings encourage the use of this route of processing as a balanced approach between low-cost and highperformance titanium alloys.
Ti-6Al-4V Blended elemental Thermomechanical processing Microstructure Fatigue
Romero Carlos Yang Fei Bolzoni Leandro
Waikato Centre for Advanced Materials,School of Engineering,The University of Waikato,Private Bag 3105,Hamilton 3240,New Zealand
国际会议
北京
英文
964-968
2018-09-16（万方平台首次上网日期，不代表论文的发表时间）