Method of adhesive bonding of heat-stable substrates, comprising the steps of: i) applying a one-component thermosetting epoxy resin composition to the surface of a heat-stable substrate S1, especially of a metal; ii) contacting the thermosetting epoxy resin composition applied with the surface of a further heat-stable substrate S2, especially of a metal, where the thickness of the thermosetting epoxy resin composition applied is ≥ 0.8 mm, especially ≥ 1 mm, after step ii); iii) heating the composition to a temperature of 100-220°C, especially of 120-200°C, preferably between 130 and 150°C, more preferably between 130 and 140°C; wherein the one-component thermosetting epoxy resin composition comprises: a) at least one epoxy resin A having an average of more than one epoxy group per molecule; b) at least one latent curing agent for epoxy resins B; c) at least one toughness improver D; where the weight ratio of the at least one epoxy resin A having an average of more than one epoxy group per molecule to the at least one toughness improver D is 0.3-2.2, and wherein the toughness improver D is a terminally blocked polyurethane prepolymer of the formula: where R 1 is a p-valent radical of a linear or branched polyurethane prepolymer terminated by isocyanate groups after the removal of the terminal isocyanate groups; p has a value of 2 to 8; and R 2 is a blocking group which is detached at a temperature above 100°C, where R 2 is independently a substituent selected from the group consisting of and ---O-R 18 where R 5, R 6, R 7 and R 8 are each independently an alkyl or cycloalkyl or aralkyl or arylalkyl group or R 5 together with R 6, or R 7 together with R 8, form part of a 4- to 7-membered, optionally substituted ring; R 15, R 16 and R 17 are each independently H or an alkyl group or an aryl group or an aralkyl group; and R 18 is an aralkyl group or is a mono- or polycyclic, substituted or unsubstituted aromatic group optionally having aromatic hydroxyl groups, wherein the one-component thermosetting epoxy resin composition has a maximum linear expansion Max. elongation of ≥ 1.65 mm, determined in a lap shear test during the cooling of a heated cured lap shear specimen, and wherein the maximum linear expansion Max. elongation is measured in a lap shear test at a strain rate V st of 0.40 mm/min, and wherein the temperature of the lap shear specimen in the lap shear test is 180°C, especially 190°C, at the start of the measurement and the lap shear specimen is cooled at the start of the measurement at a cooling rate of 40°C/min to a temperature of 25°C and then left at that temperature, where the lap shear test is a lap shear test for determination of lap shear strength according to DIN EN 1465. i) applying a one-component thermosetting epoxy resin composition to the surface of a heat-stable substrate S1, especially of a metal; ii) contacting the thermosetting epoxy resin composition applied with the surface of a further heat-stable substrate S2, especially of a metal, where the thickness of the thermosetting epoxy resin composition applied is ≥ 0.8 mm, especially ≥ 1 mm, after step ii); iii) heating the composition to a temperature of 100-220°C, especially of 120-200°C, preferably between 130 and 150°C, more preferably between 130 and 140°C; wherein the one-component thermosetting epoxy resin composition comprises: a) at least one epoxy resin A having an average of more than one epoxy group per molecule; b) at least one latent curing agent for epoxy resins B; c) at least one toughness improver D; a) at least one epoxy resin A having an average of more than one epoxy group per molecule; b) at least one latent curing agent for epoxy resins B; c) at least one toughness improver D; where the weight ratio of the at least one epoxy resin A having an average of more than one epoxy group per molecule to the at least one toughness improver D is 0.3-2.2, and wherein the toughness improver D is a terminally blocked polyurethane prepolymer of the formula: where R 1 is a p-valent radical of a linear or branched polyurethane prepolymer terminated by isocyanate groups after the removal of the terminal isocyanate groups; p has a value of 2 to 8; and R 2 is a blocking group which is detached at a temperature above 100°C, where R 2 is independently a substituent selected from the group consisting of and ---O-R 18 where R 5, R 6, R 7 and R 8 are each independently an alkyl or cycloalkyl or aralkyl or arylalkyl group or R 5 together with R 6, or R 7 together with R 8, form part of a 4- to 7-membered, optionally substituted ring; R 15, R 16 and R 17 are each independently H or an alkyl group or an aryl group or an aralkyl group; and R 18 is an aralkyl group or is a mono- or polycyclic, substituted or unsubstituted aromatic group optionally having aromatic hydroxyl groups, wherein the one-component thermosetting epoxy resin composition has a maximum linear expansion Max. elongation of ≥ 1.65 mm, determined in a lap shear test during the cooling of a heated cured lap shear specimen, and wherein the maximum linear expansion Max. elongation is measured in a lap shear test at a strain rate V st of 0.40 mm/min, and wherein the temperature of the lap shear specimen in the lap shear test is 180°C, especially 190°C, at the start of the measurement and the lap shear specimen is cooled at the start of the measurement at a cooling rate of 40°C/min to a temperature of 25°C and then left at that temperature, where the lap shear test is a lap shear test for determination of lap shear strength according to DIN EN 1465.