Inhibiting effect of Benzotriazole on the stress corrosion cracking of Cu-27%Ni cupronickel and Cu-30%Zn brass in Mattsson’s solution

•Assessment of inhibitor performance of BTA during SSRT of Cu-Zn and Cu-Ni alloys.•For the first time, exploring the inhibition efficiency under mechanical load.•Recognition the SCC fracture mode with and without presence of inhibitor.•Altering the fracture type from intergranular to ductile fracture as inhibitor effectiveness.