  We consider difference schemes for nonlinear time fractional Klein-Gordon
type equations in this paper. A linearized scheme is proposed to solve the
problem. As a result, iterative method need not be employed. One of the main
difficulties for the analysis is that certain weight averages of the
approximated solutions are considered in the discretization and standard energy
estimates cannot be applied directly. By introducing a new grid function, which
further approximates the solution, and using ideas in some recent studies, we
show that the method converges with second-order accuracy in time.
