Selective laser melting (SLM) opens the possibility to produce porous structures with designed mechanical characteristics. This study focuses on the coupling effect between unit cell topology (Dode and body‐centered cubic (BCC)) and forming orientation (horizontal and vertical) with regard to the actual geometric characterization and mechanical properties of SLM produced Ti6Al4V porous structures. The results show that for the mechanical response, there is a coupling effect between forming orientation and unit cell topology. This is most pronounced for the Dode topology, where the compressive and yield strength for specimens produced in vertical orientation are increased with 14.6% and 7.5% compared with those build horizontally. However, for the BCC topology, this effect cannot be seen. The fatigue properties for specimens processed vertically are better compared with those processed horizontally, especially for the BCC topology, it shows an increase of 51.6%. This study presents initial findings on how to handle the selection of unit cell topology and forming orientation for porous structures prepared using SLM, which may be beneficial for different applications.

Hot isostatic pressing (HIP) is an ideal fabrication technique for products with complex structure, but also a reliable post-treatment method. The individual effect of the HIP or HIP post-treatment (HIPPT) on the mechanical properties of powder compacts have been investigated, but little attention has been paid to their combined effect. In this study, the effect of HIPPT on the densification, microstructure and mechanical properties of HIPed powder compacts were investigated. The relative density shows a regional increase after HIPPT. The interlayer spacing of lamellar α phase is increased, equiaxial grains are coarsened and high-angle grains are decreased. Moreover, an obvious increase in elongation is detected, which demonstrates that HIPPT is beneficial to improve the properties of HIPed powder compacts.

The product preparation and surface carburizing of Ti-6Al-4V alloy are usually carried out separately, which leads to a low production efficiency and high processing costs. In this study, hot isostatic pressing (HIP) was proposed to complete the product preparation and surface carburizing of Ti-6Al-4V alloy simultaneously. Ti-6Al-4V powder compact with carburized layer is successfully fabricated using this method. X-ray diffraction and Energy dispersive spectrometer analyses illustrate the carburized layer is mainly composed of C, TiC and Ti. Scanning electron microscope shows a uniform TiC layer and an obvious diffusion region in the carburized layer and the total thickness is about 104 μm. The Ti-6Al-4V region is composed of equiaxed grains and typical lathlike structures. The Vickers hardness of the carburized layer especially the TiC layer is higher than the Ti-6Al-4V region. These results indicate that HIP is a promising process for product preparation and surface carburizing of Ti-6Al-4V alloy.

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