Deformability enhancement in ultra-fine grained, Ar-contained W compacts by TiC additions up to 1.1% |
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Authors: | S Matsuo H Kurishita H Arakawa T Takida M Kato Y Yamamoto K Takebe M Kawai N Yoshida |
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Affiliation: | aInternational Research Center for Nuclear Materials Science, Institute for Materials Research (IMR), Tohoku University, Narita-cho, Oarai, Ibaraki 311-1313, Japan;bA.L.M.T. Corp., Toyama, Toyama 931-8371, Japan;cInstitute of Material Structure Science, High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801, Japan;dInstitute for Applied Mechanics, Kyushu University, Kasuga, Fukuoka 816-8580, Japan |
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Abstract: | Nano-sized Ar bubbles give negative influence on the fracture resistance and occurrence of superplasticity in ultra-fine grained (UFG) W–TiC compacts. In order to enhance deformability in UFG, Ar-contained W–TiC compacts, effects of TiC addition on the high-temperature deformation behavior were examined. W–TiC compacts with TiC additions of 0, 0.25, 0.5, 0.8 and 1.1 wt% were fabricated by mechanical alloying in a purified Ar atmosphere and hot isostatic pressing. Tensile tests were conducted at 1673–1973 K (0.45–0.54 Tm, Tm: melting point of W) at initial strain rates from 5 × 10−5 to 5 × 10−3 s−1. It is found that as TiC addition increases, the elongation to fracture significantly increases, e.g., from 3 to 7% for W–0 and 0.25TiC/Ar to above 160% for W–1.1TiC/Ar when tested at 1873 and 1973 K at 5 × 10−4 s−1. The flow stress takes a peak at 0.25%TiC and decreases to a nearly constant level at 0.5–1.1%TiC. The ranges of the strain rate sensitivity of flow stress, m, and the activation energy for deformation, Q, with TiC additions are 0.17–0.30 and 310–600 kJ/mol, respectively. The observed effects of the TiC additions on the tensile properties are discussed. |
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Keywords: | Tungsten TiC dispersoids Superplasticity Elongation Deformation mechanism |
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