When it is difficult to deposit a material A on a material B, it is possible to create a Functionally Graded Material (FGM) using a buffer material between them to avoid the appearance of defects. The literature shows that it is very difficult, nay impossible, to have an efficient metallurgical bond between Ti6Al4V and Inconel-Mo alloys without cracks, porosities or delamination. A buffer material is therefore needed (here 25% Ti6Al4V -75% Mo) and the fine analysis of the two interfaces thus created makes it possible to define the relevance of the choice of the buffer. Moreover, the understanding of the phenomena taking place at the interface allows the preservation of the structural integrity of a FGM made by additive manufacturing. CLAD® powder-based directed energy deposition allows the building of parts containing FGM and/or buffer materials directly during the process. The study of the interfaces at both sides of the buffer material is essential. In this paper, the first interface 100 Ti6Al4V / 25 Ti6Al4V -75 Mo (in wt%) is smooth, suggesting that there has been diffusion between both alloys. The second one, 25 Ti6Al4V -75 Mo / 30 Inconel 718 -70 Mo, contains numerous exotic structures between both alloys. For such a sharp interface, we show in this paper that a microscopic study is not sufficient, but a finer scale is necessary to have a good metallurgical insight. Thus, EDS, TKD and X-ray crystallography were performed right on this interface and revealed three main structures: a hexagonal matrix, a cubic structure and an ordered hexagonal one. The hexagonal matrix appears to consist of Ni 3 Ti and the ordered hexagonal one of NiMo.
This paper focuses on the physicochemical changes that happen in cold mix asphalts during curing, and more specifically, while and after transitioning to different simulated seasons. Several tests were carried out in order to better grasp the influence of the weather (temperature and humidity) on the curing of such materials. The mechanical behaviour of the mix was assessed using oedometer tests. The physicochemical evolutions of extracted binders, such as oxidation and rheology, were evaluated. The results show stiffening of the mix and ageing of the binder linked to a higher temperature and a lower humidity. A low temperature and high moisture seem to slow down these evolutions. However the binder behaviour does not explain the whole mix behaviour as the kinetics between them are not always similar. Thus other mechanisms are yet to be found and taken into account to fully understand cold mix asphalts behaviour.
This paper focuses on the physicochemical changes that happen in cold mix asphalts during curing, and more specifically, while and after transitioning to different simulated seasons. Several tests were carried out in order to better grasp the influence of the weather (temperature and humidity) on the curing of such materials. The mechanical behaviour of the mix was assessed using oedometer tests. The physicochemical evolutions of extracted binders, such as oxidation and rheology, were evaluated. The results show stiffening of the mix and ageing of the binder linked to a higher temperature and a lower humidity. A low temperature and high moisture seem to slow down these evolutions. However the binder behaviour does not explain the whole mix behaviour as the kinetics between them are not always similar. Thus other mechanisms are yet to be found and taken into account to fully understand cold mix asphalts behaviour.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.