Identification of the Critical Pore Sizes in Sintered and Ecaped Aluminium 6XXX Alloy

Abstract

The main aim of this paper is to investigate, by means of comparison of experimental studies and mathematical models, the evolution of porosity as consequence of pressing, sintering and ECAPping an aluminium based powder (6xxx). After applying the compacting pressure, specimens were dewaxed in a ventilated furnace at 400• C for 60 min. Sintering was carried out in a vacuum furnace at 610• C for 30 min. The specimens were then ECAPed for 1 pass. The 2-dimensional quantitative image analysis was carried out by means of SEM and OM for the evaluation of the aforementioned characteristics. Results show the effect of processing parameters on the fracture/microstructure behaviour of the studied aluminium PM alloy. Quantitative image analysis, as well as fractographic interpretation and microstructure identification of weak sites in the studied aluminium PM alloy, provide a reliable and reproducible statistical procedure for the identification of the critical pore sizes.Keywords: aluminium alloy, ECAP, porosity, critical pore sizes, microstructure, fracture Głównym celem pracy jest badanie zmian porowatości podczas prasowania, spiekania i wyciskania przez kanał kątowy proszku na bazie aluminium (Ai-Mg-Si-Cu-Fe) za pomocą eksperymentu i symulacji numerycznych. Po przyłożeniu ciśnienia podczas zagęszczania usuwano lepiszcze z próbek w piecu w temperaturze 400• C przez 60 minut. Spiekanie prowadzono w piecu próżniowym w temperaturze 610• C przez 30 min. Próbki następnie były wyciskane przez kanał kątowy w jednym przejściu. Dwuwymiarową ilościową analizę obrazu przeprowadzono za pomocą skaningowej mikroskopii elektronowej i mikroskopii optycznej w celu oceny wyżej wymienionych właściwości. Wyniki opisują wpływ parametrów procesu na pęka-nie/mikrostrukturę badanego proszku stopu aluminium. Ilościowa analiza obrazu, jak również mikrostruktury w badanym stopie proszku aluminium zapewniają wiarygodne i statystycznie powtarzalne procedury dla identyfikacji miejsc inicjacji pękania.

A Compacting Process of the en Aw 6060 Alloy

“…The method of forward extrusion of chips involves compacting the chips at ambient temperature, followed by extrusion at an elevated temperature. In the first stage, the chips are mechanically compacted and are then pressed [13]. Within the arrangement of the chips, open porosity emerges which is not fully removed in the second stage of processing.…”

“…The first stage of processing is therefore very important. The most widely-used methods for extruding of compacted chips are forward extrusion [17,18], extrusion through bridge dies [2,4,13], and new technologies, such as equal channel angular pressing (ECAP) [20][21][22][23] and friction stir wire extrusion [24].…”

New Approach In The Properties Evaluation Of Ultrafine-Grained OFHC Copper

“…Experimental data about the role of subsurface evaluation in terms of workability is still limited, especially in a newly progressive processing -ECAP, orbital forming [55][56][57], where workability is one of the most important artefact in UFG materials, according to Kvačkaj [58]. The results of wear rate vs sliding distance are presented in Fig.…”

Laser Powder Bed Fusion of Aluminum Alloys

“…Also the role of porosity represent the problem related to the mechanical properties. The investigation of the porosity behavior of aluminum alloys is reported in [24][25][26][27].…”