Research On Fabrication Of Light Alloy Multilayered Plate By Accumulative Roll-Bonding(ARB)with Large Number Of Cycles

Currently, Magnesium alloys and Aluminium alloys are widely used in industries, and in order to take full advantage of the rich resources of Mg and Al, it is quite important to develop advanced materials bearing Mg and Al. Heterogeneous metal multilayered materials could synthesize advantages of heterogeneous metals and obtain excellent comprehensive properties. In this research, accumulative roll-bonding (ARB) processing technology with large number of cycles was used to prepare the light metal nano-multilayered materials.Firstly, AZ31wrought magnesium alloy and1060pure aluminium multilayered plate was deformed by ARB with8cycles at400℃, and the plate was rolled by5passes in each cycle. The rolling reduction of every pass was15%, and the total reduction of each cycle was about75%. Due to the formation of Mg/Al intermetallic compounds (Mg17Al12) and the disappearance of the layer interface during the ARB process, the multilayered structure is difficult to achieve in the Mg/Al multilayered plate, and the tensile strength of the plate is significantly decreased. However, the bonding degree of layer interfaces is effectively improved through the formation of the intermetallic compounds. With the increase in the number of ARB cycle, the intermetallic compounds are significantly refined, and the continuous multilayered morphology of intermetallic compounds is gradually observed.Secondly, multi-wall carbon nano-tubes (CNTs) were impregnated between the1060pure aluminium plates. The ARB process was repeated8cycles, and the plate was preheated at250℃before rolling. In each cycle, the plate was rolled by3passes, the rolling reduction of every pass was25%, and the total reduction of each cycle was about75%. The results indicate that the multilayered structure of1060pure aluminium plates with CNTs can be seen obviously during the ARB process, but the layer interfaces are not bonded well in the first few ARB cycles. The layer interfaces between1060pure aluminium and CNTs are well-bonded only after3ARB cycles being done at least. Meanwhile, the bonding degree of layer interfaces is gradually improved with the increase in the number of ARB cycles, which lead the increase of the tensile strength of the Al/C multilayered materials with the ARB cycles. After8cycles ARB processing, part of the CNTs are dispersed into Al matrix, but the Al/C multilayered structure are still observed.Thus, in order to fabricate the nano-multilayered materials with heterogeneous metals by ARB process, it is necessary to avoid the chemical reactions between heterogeneous metals, in which the intermetallic compounds can be easily formed. Meanwhile, the bonding degree of layer interfaces between heterogeneous metals should be improved continuously during ARB process, by which the better mechanical properties of the heterogeneous metal multilayered materials can be achieved obviously.