Effect of Volume Fraction of Ti on Microstructure Evolution and Thermal Properties of Al/Ti Laminated Composites.

This paper examines the microstructure evolution and thermal properties of Al/Ti composites with different volume fractions of Ti. The laminated composites were first fabricated by the accumulative roll bonding (ARB) process. The fabricated composites were then stacked and bonded together by cold roll bonding process to produce Ti–Al functionally graded composite. The microstructural investigation of ARBed composites revealed that plastic instabilities including necking and rupture took place within composites. As a result, the fragments of Ti were distributed uniformly across the Al matrix. In addition, the SEM images of the Al–Ti functionally graded composite showed a compositional gradient from the Al side to the Ti side. Based on the EBSD maps taken from Al and Ti layers, the grain refinement was successfully achieved during six passes. Besides, with an increase in the volume fraction of Ti, the grains became finer, indicating the gradient in grain size across Al–Ti functionally graded composite. Furthermore, the experimentally measured thermal properties of Al and Ti sheets increased as a function of temperature while they declined by increasing passes. However, thermal conductivity, thermal diffusivity, coefficient of thermal expansion, and specific heat capacity of Al/Ti composites showed a reduction with the rise of Ti content. [ABSTRACT FROM AUTHOR]