DEFORMATION MECHANISMS IN HIGH-PURITY FE-50CR(-5W) ALLOYS AT ELEVATED-TEMPERATURES

The deformation mechanisms in high-purity Fe-50Cr(-5W) alloys were inv estigated between 293 and 773 K by tensile tests and by TEM observatio ns of the fractured specimens. The results of the TEM observation have shown the following. 1. Fe-50Cr alloys deform by dislocation slip and twinning. 2. Four types of twin-matrix interfaces are observed in hig h purity Fe-50Cr(-5W) alloys after deformation, normal type, zigzag ty pe, wavy type and abnormal type. 3. The planar slip traces are seen on the Fe-SOCr alloy after deformation at 293 and 573 K and the addition of tungsten restrains the local deformation. The results of the tensi le test have shown the following. 4. The addition of tungsten to an Fe -SOCr alloy increases the amount of twinning at every temperature and the elongation of high-purity Fe-SOCr alloy increases dramatically at 773 K due to uniform dislocation slip.