Deformability enhancement in ultra-fine grained, Ar-contained W compacts by TiC additions up to 1.1%
Deformability enhancement in ultra-fine grained, Ar-contained W compacts by TiC additions up to 1.1%
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DOI：
10.1016/j.msea.2008.05.012
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发表时间：
2008-09
期刊：
影响因子：
6.4
通讯作者：
S. Matsuo;H. Kurishita;H. Arakawa;T. Takida;M. Kato;Y. Yamamoto;K. Takebe;M. Kawai;N. Yoshida
中科院分区：
文献类型：
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作者：
S. Matsuo;H. Kurishita;H. Arakawa;T. Takida;M. Kato;Y. Yamamoto;K. Takebe;M. Kawai;N. Yoshida
纳米级Ar气泡对超细晶(UFG)W-TiC压坯的抗断裂性和超塑性的发生有负面影响。为了提高超细粉末冶金中的变形能力，研究了添加TiC对含Ar的W-TiC粉末高温变形行为的影响。采用纯Ar气氛机械合金化和热等静压工艺制备了TiC加入量分别为0、0.25、0.5、0.8和1.1wt%的W-TiC压坯。在1673-1973K(0.45-0.54Tm，Tm：W的熔点)，初始应变速率从5×10−5到5×10−3s−1的拉伸试验发现，随着TiC加入量的增加，断裂伸长率显著增加，如在1873和1973K下，W-0和W-1.1TiC/Ar的断裂伸长率分别从3%~7%和0.25TiC/Ar增加到160%以上，在5×10−4s−1下，流动应力在0.25%TiC时出现峰值，在0.5%~1.1%TiC时几乎保持不变。添加TiC后，流动应力的应变速率敏感性m和变形激活能Q的范围分别为0.17-0.30和310-600kJ/mol。讨论了TiC加入量对拉伸性能的影响。
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 1.1wt% were fabricated by mechanical alloying in a purified Ar atmosphere and hot isostatic pressing. Tensile tests were conducted at 1673–1973K (0.45–0.54Tm, Tm: melting point of W) at initial strain rates from 5×10−5to 5×10−3s−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 1973K at 5×10−4s−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 310–600kJ/mol, respectively. The observed effects of the TiC additions on the tensile properties are discussed.