The Effect of Microstructure on Mechanical Properties of Forged 6061Aluminum Alloy

摘要

A novel process to improve mechanical properties of forged 6061 aluminum alloy has beenrndeveloped. The retention of subgrains developed during hot forging at low Z,rnZener-Hollomon, parameter conditions leads to enhancement of mechanical propertiesrncompared to those of conventionally recrystallized ones. The yield strength of thernsubgrained 6061 aluminum alloy is 350MPa, which is higher than 6X51 aluminum alloysrnwith excess Si. The strengthening stems from dislocation strengthening and fine grainedrnstrengthening through Hall-Petch relation. Fracture toughness of the subgrained 6061rnaluminum alloy, which breaks by transgranular fracture, is 10% higher than that ofrnrecrystallized ones, which fail by intergranular fracture. It is proposed that developmentrnof Al-Mg-Si alloys with excellent mechanical properties requires a subgrain structure thatrncan be achieved by hot-forging at low Z parameter conditions.