Abstract: To understand the effect of hydrogenation and deformation rate on the property of alloy BT16 for cold heading, the shear band of a compression sample of a hydrogenated alloy BT16 specimen is investigated by means of optical microscope (OM) and microhardness test. The results show that the deformed flow line is parallel to the shear band formed at a deformation rate of 300 mm/s. There is no clear boundary between the central zone and transition zone in the shear band, and there is a small angle between the deformed flow line and the shear band formed at the deformation rate of 75 mm/s. When the shear band is formed at the deformation rate of 300 mm/s, the microhardness value is approximately constant in the central zone of the shear band, and it is lower than that in the matrix. There is a transition zone between the central zone of the shear band and the matrix, in which the microhardness value increases linearly with the test point moving from the central zone of the shear band to the matrix. The formation process of the shear band is analyzed and a calculating method of the shear band strain is proposed by means of the deformed flow line.

Key words: alloy BT16, hydrogenation, shear bands, microhardness, strain