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Content available remote Substituting Ti-64 with AA2099 as material of a commercial aircraft pylon
EN
The aircraft industry is striving to reduce the weight of aircraft to save fuel and hence reduce total cost. New alloys and composites with properties such as low weight and high strength are continuously developed. Titanium alloys have the best strength-to-weight ratio among metals which makes them very suitable for aircraft applications. Ti-64 is the most common Titanium alloy used in aircraft. AA2099 is a 3rd generation Al-Li alloy and has the lowest density among all Aluminium alloys making it very attractive for aircraft applications. Pylons of commercial aircraft are currently made primarily with Ti-64 and this study focused on the replacement of Ti-64 with AA2099. Loading conditions, operating temperature, corrosion resistance, manufacturability and recyclability of the pylon were analysed of both Ti-64 and AA2099. Three critical scenarios were chosen for the loading conditions of the pylon. These were simulated using finite element analysis first using Ti-64 and then AA2099. From the results, it is evident that using AA2099 as the material of the pylon instead of Ti-64 offered weight savings. The operating temperature, manufacturability and recyclability also showed advantages when using AA2099 whereas corrosion factors favoured Ti-64, since AA2099 was found to be very prone to galvanic corrosion.
EN
In this study, binary Al–2.3wt%Li alloy, ternary Al–2.2wt%Li–0.1wt%Zr alloy and quaternary Al–2.2wt%Li–0.1wt%Zr–1.2wt%Cu alloy in the solution treated condition and additionally in aging condition were severely plastically deformed by rolling with cyclic movement of rolls (RCMR) method to produce ultrafine grained structure. Scanning transmission electron microscopy (STEM), scanning electron microscopy with EBSD detector (SEM/EBSD) were used for microstructural characterization and hardness test for a preliminary assessment of mechanical properties. The results shows, that the combination of aging treatments with RCMR deformation can effectively increase the hardness of Al–Li alloys. Second particles hinders the annihilation of dislocations in Al matrix during deformation leading to an increase of dislocation density. Significant amount of nanometric second particles in refined structure to ultrafine scale especially in Al–2.2wt%Li–0.1wt%Zr–1.2wt%Cu alloy effectively prevents the formation of high angle boundaries.
EN
The present study demonstrate the effect of the combined deformation (hydrostatic extrusion and rolling) on microstructure and mechanical properties of model Al-Li alloys. It has been shown the anisotropy of material structure and properties. Additionally it has been demonstrated increase of yield strength at the result of the plastic deformation.
PL
W pracy przedstawiono wpływ łączonego odkształcenia wyciskania hydrostatycznego i walcowania na zimno na mikrostrukturę i właściwości modelowych stopów Al-Li. Badania wykazały obecność anizotropii struktury materiału i właściwości. Ponadto przedstawiono wzrost wła-ściwości wytrzymałościowych w wyniku odkształcenia plastycznego.
EN
The influence of the solution treatment on microstructures and mechanical properties of 2099 Al–Li alloy was investigated by means of optical microscopy, scanning electron microscopy, transmission electron microscopy and tensile properties measurement. With increasing solution temperature, the quantity of primary particles in the alloy decreased, and the degree of recrystallization gradually increased, leading to softening of solution treated alloy. Dissolution of primary particles in the solution treatment process promoted δ′ and T1 phases to precipitate during sequent aging treatment resulting in increase of strength. The number of T1 phases increased to peak value when the alloy was solution treated at 540 °C because almost no further dissolution of Cu-containing particles occurred at higher temperature. However, exorbitant solution temperature caused the drastic increase in the size and quantity of recrystallized grains that softened the alloy. Thus, mechanical properties of aged alloy were determined by two mechanisms: precipitation strengthening and solution softening. Compared with solution temperature, solution time had less effect on microstructures and mechanical properties of alloy. The suitable solution treatment for 2099 Al–Li alloy was 540 °C for 1 h, treated by which the yield strength of the aged alloy was 604 MPa with the elongation of 7.9%.
PL
W pracy poddano analizie rolę, jaką odgrywają poszczególne pierwiastki dodawane do stopów na osnowie AL-Li (Li, Zr i Cu) w kształtowaniu tekstury i anizotropii własności plastycznych podczas ich walcowania na gorąco oraz następującym po nim umocnieniu wydzieleniowym. Badaniom poddano trzy modelowe stopy: Al-Li, Al-Li-Zr i Al-Li-Cu-Zr po walcowaniu epsilon=1,2, 1,8 i 2,5. Ujawniono duże zmiany wartości współczynnika Lankforda pomiędzy kierunkiem walcowania i kierunkiem poprzecznym blach. Do przewidywania anizotropii własności plastycznych użyto modelu Taylora i CMTP bazujących, na ilościowym pomiarze tekstury. Na ogół model CMTP daje lepszą zgodność z wartościami eksperymentalnymi.
EN
The specyfic of Li, Zr and Cu alloying elements in Al-Li alloys have been investigated in terms of their influence on texture and plastic anisotropy evolutions during hot rolling and subsequent precipitates hardening. Three model alloys: Al-Li, Al-Li-Zr and Al-Li-Cu-Zr alloys were analysed after deformation of epsilon=1,2, 1,8 and 2,5. Pronounced plastic anisotropy of Lankford coefficient were measured between rolling and transverse direction of sheet. The quantitative texture data was used together with the CMTP and Taylor models to predict the anisotropy. In general the CMTP model gave a reasonable correlation with the experimental values.
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