Microstructure, basic thermal-mechanical and Charpy impact properties of W-0.1 wt.% TiC alloy via chemical method

摘要

W-0.1 wt.% TiC materials with different rolling reduction (65% and 83%) were fabricated by wet chemical method, medium-frequency induction sintering and hot rolling and their microstructures, chemical composition, basic mechanical properties, high temperature tensile properties and Charpy impact properties were characterized. For comparing, commercial pure tungsten powders were sintered and hot rolled with the same procedure. The results revealed that the heavily elongated TiC particles were uniformly distributed in the grain interiors. In addition, the intragranular TiC particles combining with severe plastic deformation could refine the grain size and increase both the strength and toughness of tungsten materials remarkably. The W-TiC alloy with rolling reduction of 83% exhibited the highest bending strength of 1260 MPa, the highest tensile elongation of 19.3% and 13.6% at 300 and 600 degrees C respectively, the highest Charpy absorbed energies at 400-900 degrees C and the lowest DBTT of about 450 degrees C. In contrast, the pure tungsten with the same rolling reduction displayed the lowest bending strength of 1035.4 MPa, the lowest tensile elongation of 12.1% and 9.3% at 300 and 600 degrees C respectively, the much lower Charpy absorbed energies at 400-900 degrees C and the higher DBTT of 650 degrees C. Interestingly, pure tungsten with more rolling reduction resulted in larger grain size due to their low recrystallization temperature. Conversely, the W-TiC alloys achieved smaller grain size with more rolling reduction due to the elevated recrystallization temperature by the addition of TiC particles. Another interesting phenomenon is that the total tensile elongations of the samples tested at 600 degrees C were all lower than the samples tested at 300 degrees C. The reason was attributed to the different moving behavior of the dislocations at different tensile test temperatures. (C) 2015 Elsevier B.V. All rights reserved.