Dear Amirhossein,
irace is a tool for configuring (tuning) hyper-parameters of algorithms, optimization algorithms, machine learning models, compilers, database managers, etc.
mlr is a framework for machine learning in R.
You can use irace to tune other machine learning packages/models not in mlr (for example, scikit-learn).
You can also use other algorithms to tune the machine learning models in mlr.
I hope the above clarifies the difference between irace and mlr.
Best,
Manuel.