Formability of Ni/Al micro-laminated composite sheet

Abstract:

The Ni/Al micro-laminated composite sheet was prepared by the vacuum hot pressing method. The mechanical properties and crack initiation and propagation laws of Ni/Al micro-laminated composite sheet were studied through uniaxial tensile experiments under different temperatures and different deformations degree. The results show that the Ni/Al micro-laminated composite sheet has poor plasticity from room temperature to 400°C, and when the deformation is only 5%, the NiAl3 and Ni2Al3 intermetallic compound layer has produced more cracks perpendicular to the tensile direction. The Ni/Al micro-laminated composite sheet exhibits good plastic deformation ability at 600℃, with the elongation at break as high as 56%, and when the deformation reaches 20%, the NiAl3 layer begins to appear microcracks, and the crack does not propagate to Ni2Al3 layer and Al layer when the deformation reaches 50%. The pressure free bulging experiment was used to study the forming performance of the Ni/Al micro-laminated composite sheet at 600℃, and the microstructure distribution of the bulging part was characterized. The results show that the limit bulging rate (limit bulging height/die diameter) of Ni/Al micro-laminated composite sheet at 600℃/5.5MPa/8min can reach 36.7%. The wall thickness of the gas bulged spherical shell gradually decreases from the bottom to the top, the top Ni and Al layers were severely necked, and cracks occurred in the NiAl3 layer, but they did not extend to the Ni2Al3 layer and the Al layer.

Key words:Ni/Al micro-laminated composite; Mechanical properties; Crack;Formability