Microforming of superplastic 2091Al-Li alloy

Stainless die with micro-groove and micro-hole have been designed and manufactured, which has been used to study superplastic microforming of 2091Al-Li alloy by means of superplastic forming. Micro-extrusion test shows that the selected material has good microformability which is evaluated by the specially developed method. Effects of pressure on forming have been analysed. At 510 degreesC, the width of ribs are 160 mum and 140 mum respectively in case 1 (stress 63.69 MPa, dwell time 6 min) and case 2 (stress 79.62 MPa, dwell time 5 min). SEM and metallo-graphic microscope have been used to analyse the surface of the formed micro-rib and micro-protuberance. At 500 degreesC, stress 79.62 MPa and dwell time 5 min, the diameter of the micro-protuberance is 150 mum. Through analysis of flow lines of the formed micro-rib specimen behavior of material could be understood well.