Cyclic hardening of tungsten monofilament-reinforced monocrystalline copper matrix composites

The cyclic hardening of fiber-reinforced metal matrix composites has been explored using tungsten monofilament-reinforced monocrystalline copper composite specimens. This composite showed the same overall hardening tendencies as monolithic copper single crystals, i.e. rapid hardening, momentary softening and saturation, but at much higher stress levels as compared to the behavior in the copper single crystals. The back stress of the composites was found both very high and much larger than the friction stress so that there was a pronounced Bauschinger effect. The high cyclic stress in the composite was predominantly due to the back stress which resulted from the interaction between the fiber and dislocations. The fiber did not have a significant effect on the friction stress.