The present numerical simulations are carried out to investigate the effect of viscous dissipation, temperature dependent viscosity and heat source/sink on magnetohydrodynamics (MHD) unsteady Carreaue nanofluid over a cone filled with different alloy nanoparticles. We considered two different types of alloy nanoparticle namely nickel chromium iron alloy (Nimonic 80A) and titanium aluminum vanadium alloy (Ti%6Al%4V). The governing equations of the flow are solved using the Runge-Kutta and Newton's method. The present numerical results are compared with the previous study and found agreement with the uncertainty of +/- 2.5%. Effects of various non dimensional parameters such as Eckert number, power index parameter, volume fraction, heat source/sink parameter, viscous variation parameter and semi-vertical angle of the cone on the momentum and thermal boundary layer including the friction factor coefficients and local Nusselt number are presented and analyzed for two different alloy considered in the present study. It is found that the viscous variation parameter enables to enhance the heat transfer rate. The Ti%6Al%4V alloy has higher friction factor coefficient along the azimuthal direction of the flow while Nimonic 80A alloy boosts up the friction coefficient along the tangential direction. It is worth to mention that the heat transfer rate of Nimonic 80A alloy is higher than that of Ti%6Al%4V alloy. Hence, Nimonic 80A alloy signifies a better thermal performance than the Ti%6Al%4V alloy. (C) 2017 Elsevier B.V. All rights reserved.