Effects Of Heatment And Deformation On High-temperature Internal Friction Of Al-Ce Alloys

The internal friction as a very sensitive physical quantity to the structure will showvarious characteristics, along with motions of internal structure and defects. The studyof applications of rare-earth for metallurgy industries especially for steel and ironsmelting is the most complete. And non-ferrous metals smelting is followed. Theaddition of rare-earth elements can refine the macro and micro organization，andimprove the heat resistance, corrosion resistance and mechanical properties. Asrare-earth elements are more and more widely used in Al and Al alloys, studying whatroles rare-earth elements play in Al and Al alloys becomes more and more important.Cold drawing wires of rare-earth aluminum alloys will experience the processes ofrecovery, recrystallization, secondary recrystallization and so on, in the processing ofheatment and deformation. At the same time the grain boundary structure anddislocation around grain boundaries will experience complex movements. Study of thehigh-temperature internal friction about rare-earth aluminium alloys, espesically grainboundary internal friction, can show existential states of rare-earth in grain boundariesand effects on grain boundaries.The internal friction of Al-0.600wt%Ce and Al-1.00wt%Ce alloys passed throughannealing treatment or cold deformation, was measured by the internal frictionequipment. There were mainly three parts of experiments: effects of annealingtemperature, annealing time and deformation ratio on high-temperature internal frictionof Al-Ce alloys. Through the comprehensive analysis of internal friction curves,including peak temperature, peak values and activation energy, the paper aims toexplore how internal friction curves shift accordingly with different structure states andstructure defects. Furthermore, it also aims to probe into the effects of rare-earth Ce ongrain boundary internal fiction, with metallographic experiments as supplements.The results were as follows.1. Three internal friction peaks were observed inAl-0.600wt%Ce and Al-1.00wt%Ce alloys after different annealing treatments. First,traditional grain boundary internal friction peaks were found between505K and530Kin samples after annealing at lower temperature. Second, in high temperature side of the traditional internal friction peak appeared a solid solution grain boundary peak. Third,Bamboo grain boundaries peaks were found in samples after annealing at highertemperature.2. Internal friction values fell dramatically at a certain temperature atwhich secondary recrystallization began. With the increase of deformation ratio, thetemperature at which internal friction fell dramatically and secondary recrystallizationbegan, reduced.3. The temperatures and values of traditional grain boundary internalfriction peaks were reduced because of the addition of rare-earth Ce. And the morerare-earth Ce added, the smaller the values were and the lower temperatures the peaksmoved to. The addition of rare-earth Ce also made grains refined.