| Summary: | 碩士 === 國立交通大學 === 機械工程系 === 90 === Nickel is a versatile material in the industrial world owing to its excellent strength at high temperature, strong resistance to corrosion, excellent magnetic and tensile properties. Today, Nickel is used to strengthen many metals that include copper, stainless steel, platinum, etc.
The Gleeble machine was used to study the thermal mechanical properties of Nickel and other target materials. After hotworking, the stain-stress relation and metallographic observation were analyzed . The experiments include: Compression testing, OM, X-Ray diffraction analysis, metallurgical observation. The manufacturing process diagram was also developed and constructed for the Nickel target.
The experimental results for the Ni target show that:
(1) The forming stress, during forging at different thermal gradients, can reach a state of strain softening, stabilizing or even dynamic recrystallization (DRX). The softening strain is especially evident at higher temperatures. Therefore, with the reduction of the softening strain and the increase in temperature, the DRX graph is approach to a stable curve.
(2) The effect of strain and temperature on the strength of the <111> orientation of the crystal does not follow any predefined rule.
(3) At 1050℃, the relationship between the strength and the degree of compression is roughly linear.
(4) At a strain of below 5s-1, 0.5 s-1 (1150℃) and 0.5 s-1 (1050℃), the strength in the <111> orientation are much weak and these are useful information in the production of Ni targets.
The experimental results for the other target materials are as follows:
(1)After annealing at 450℃, the grain size of AlCu and AlSi crystals become more uniform with the increase of annealing time. This is an useful information in the processing of these target materials.
(2)The crystals of NiCr(56-44), NiCrSi(47.5-47.5-5) and NiCrSiAl(50-44-4-2) are still bigger and no boundary recrystallization occurred, therefore there is no suitable process condition for these target materials.
(3) Heavy compression is suitable for manufacturing of Ti target
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