Učinak mehaničke uzbude na preko-oporavak unutarnjeg trenja legura Al-16 Wt% Ag i Al-16 Wt% Ag-0.28 Wt% Fe

The phenomenon of internal friction (IF) of Al-16 wt% Ag and Al-16 wt% Ag-0.28 wt% Fe alloys aged at 428 and 523 K was studied at different testing temperatures using the free-decay method. The wire specimens were investigated for IF recovery under two different conditions of excitation. In the first, the specimens were continuously excited and in the other, they were subjected to normal condition of restrictive excitation. Under certain conditions of heat treatment and mode of excitation, an anomalous behaviour of IF recovery has been observed. TEM investigations confirmed that addition of Fe to Al-Ag alloy accelerates the precipitation of metastable phases. The mean values of the excitation energy of both alloys were found to be equal to that quoted for precipitate-dislocation interactions.Proučavali smo pojavu unutarnjeg trenja (UT) u slitinama Al-16 wt% Ag i Al-16 wt% Ag-0.28 wt% Fe starenim na 428 i 523 K, metodom slobodnih oscilacija na nizu mjernih temperatura. UT uzoraka žice ispitivali smo dvama načinima uzbude. U prvom s neprekidnom uzbudom, a u drugom smo uzorke podvrgavali normalnim uvjetima ograničene uzbude. U nekim uvjetima toplinske obrade i načina uzbude, opazili smo anomalan oporavak UT. Ispitivanja pomoću TEM potvrdila su da dodavanje Fe slitini Al-Ag ubrzava precipitaciju metastabilnih faza. Našli smo da je srednja energija uzbudne energije obje slitine jednaka onoj koja se navodi za interakcije dislokacija s precipitatima

Utjecaj opterećenja na obnavljanje unutarnjeg trenja legura Al-16 wt % Ag i Al-16 wt % Ag – 0.28 wt % Fe

The phenomenon of internal-friction recovery of Al-16 wt % Ag and Al-16 wt % Ag - 0.28 wt % Fe alloys is studied after cold-working the samples in uniaxial tension using the free decay method. The wire samples are investigated for internal friction recovery while they were loaded, within the elastic limit, by different loads at different testing temperatures. It is found that by increasing the temporary loading, the rate of recovery decreases. TEM investigations confirmed that the addition of Fe to Al-Ag alloy accelerates the formation and coarsening of Guinier-Preston zones. The results are explained on the basis of dislocation damping adopting the Granato-Lücke model for recovery of internal friction.Proučava se pojava oporavka unutarnjeg trenja legura Al-16 wt % Ag i Al-16 wt % Ag – 0.28 wt % Fe nakon hladne obrade jednoosnim naprezanjem primjenom metode slobodnog opadanja. Ispitivali smo žičane uzorke pod opterećenjem unutar elastične granice za više opterećenja i na više ispitnih temperatura. Našli smo da se s povećanjem opterećenja smanjuje brzina oporavka. Ispitivanja TEM-om su potvrdila da dodavanje Fe leguri Al-Ag ubrzava stvaranje i okrupnjivanje G. P. zona. Ishodi se tumače Granat-L¨ucke-ovim modelom dislokacijskog gušenja za oporavak unutarnjeg trenja