Effects of process parameters on microstructure and properties of AZ91 alloy prepared by cooling/stirring and rolling process

Abstract

A sloping semisolid rheorolling process of AZ91 alloy was developed, and the effects of process parameters on microstructure and properties of AZ91 alloy strip prepared by the proposed process were investigated. The grain size and roundness of the strip increase with the increment of casting temperature, and the ultimate tensile strength and elongation of the strip decrease. The primary grain size increases with the increment of roll speed. The grain size of the strip decreases first and then increases with the increment of vibration frequency, and mechanical properties increase first and then decrease. When the casting temperature was between 670 and 690°C, the roll speed was 0·052 m s⁻¹, the vibration frequency was 80 Hz, the amplitude was 0·55 mm and the sloping angle was 45°, the AZ91 alloy strip was produced. The ultimate tensile strength of the strip is 215 MPa, and the elongation is 3·02%.

Keywords:

• Semisolid
• Sloping plate
• Twin roll casting
• AZ91 alloy strip manufacturing
• Microstructure
• Property

The authors thank the supports of the National Natural Science Foundation of China under grant no. 51034002 and no. 50974038, and the Chinese National Program for Fundamental Research and Development under grant no. 2011CB610405.