Hot tensile behavior of an extruded Al–Zn–Mg–Cu alloy in the solid and in the semi-solid state

• The first reported research into the tensile behavior of as-deformed alloy in the semi-solid state.
• Tensile behavior can be divided into three stages according to the effect of liquid.
• A brittle temperature range (519–550 °C) is proposed.
• An equation based on ultimate tensile stress and temperature was proposed.

This is the first reported research into the tensile behavior of as-deformed Al–Zn–Mg–Cu alloy in the semi-solid state. Tensile tests of extruded 7075 aluminium alloy were carried out in the high temperature solid and semi-solid states. Based on the tensile results and microstructural examination, the tensile behavior can be divided into three stages according to the effect of liquid: one behaves in predominantly ductile character between 400 and about 520 °C (fl ∼ 0.31%), one is governed by both of solid and liquid between 520 and 550 °C (fl ∼ 2%), and almost completely dominated by liquid above ∼550 °C. A brittle temperature range (519–550 °C) is proposed, in which the as-deformed Al–Zn–Mg–Cu alloy exhibits large crack probability. An equation based on ultimate tensile stress and temperature is proposed.