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Accumulative Roll Bonding TZM Alloy Properties

TZM alloy after accumulative roll bonding found with the increases rolling quantity increase, the grain is gradually refined and structure distribution is more uniform, so that the alloy’s tensile strength and interfacial bonding will get improved.

To analyze TZM alloy properties after process accumulative roll bonding found with rolling quantity increase, the tensile strength of the alloy has significantly improved. TZM alloy after ordinary rolling, the tensile strength is about 620MPa. After first accumulative roll bonding, alloy’s tensile strength of the alloy has a small decline. This is mainly because first accumulative rolling has higher preheated temperature, resulting in grain growth and recovery. Further, the accumulative rolling process will form a large dislocation multiplication, particularly in the central part, and the fiber texture is replaced by the boundary grain structure, so that the toughness of the central area disappears. Besides, after first rolling alloy’s composite surface is not stronger than matrix’s. After second and third accumulative roll bonding, the grain is further refinement, exceeding the growth rate of the grain, and therefore ultimate tensile strength reached a peak in the third accumulative roll bonding, which is about 968MPa. After the fourth accumulative rolling, strength is not going to increase, mainly because after rolling processing to process annealing the grains happen recovery and recrystallization, to inhibit the further refinement of the alloy grains. Further, alloy appears dislocation multiplication, and bonding surface effect can also affect the alloy grain refinement.

TZM alloy after accumulative roll bonding can enhance its strength and toughness. In scanning photos, only a small amount of ductile tearing signs, but in the course of tensile strength testing, alloy exhibits brittle fracture characteristics, and the maximum elongation is 2%.

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