Effect of the Method of Production of an Ni3Al/Mo Layered Composite Material on Its Structure and Properties

A stack of alternating 25 100-mu-thick Ni3Al plates and 28 200-mu m-thick Mo plates is subjected to hot isostatic pressing (HIP) at a temperature T = 1200 degrees C and a pressure P = 150 MPa for tau = 2.5 h followed by hot rolling at 1050-950 degrees C to a thickness of 2.3 mm. The stack is then subjected to cold rolling (CR) to a thickness of 0.5 mm without intermediate annealing, subsequent annealing during HIP at T = 1200 degrees C, P = 150 MPa, and tau = 2.5 h, and CR to a thickness of 0.22 mm. Upon CR at a strain epsilon changing from 80.8 to 95.8%, the following specific structure forms in the longitudinal direction: molybdenum layers acquire a wavelike structure, can contact with each other, form "cells," and retain almost the same thickness, and Ni3Al alloy layers are rejected between the molybdenum layers to form a regular structure made of alternating thickenings and thinnings across the rolling direction. Annealing during HIP and subsequent CR to epsilon = 98.2% lead to the formation of zones with a broken alternation of layers in the longitudinal and transverse directions, which is related to different strain resistances of the (more refractory) molybdenum and Ni3Al layers at 20 degrees C. The adhesion between the layers is good, and no intermediate phases form at the interface. The ultimate bending strength of the 2.3-mm-thick workpiece at 20 degrees C is 1000 +/- 100 MPa, and the prepared material has a plasticity margin.