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研究了若干烧结参数,包括预还原制度、烧结时间以及烧结后的冷却速率,和真空热处理的作用。对于抗张试样,为获得延伸率≥22％,在10分钟的加热阶段预还原就可以了。烧结时间以30～60min为最优,烧结2～3h由于孔的聚合而使性能变坏。慢冷不仅在凝固阶段是必需的,而且在该阶段以下直到800℃。采用平均冷却速率～50K/min可获得延伸率≥23％,破断应力≥1200N/mm~2。真空热处理(VHT)可以提高烧结试样之延性和强度并降低其氢含量,其最显著的效果是对于由1400℃急冷的试样。由本文的工作确信冷却敏感性的机制是氢脆,它导致急冷试样的脆性。真空热处理对延性的改善归因于氢由钨晶粒和基体间相界区域的消除。
A number of sintering parameters were investigated, including the pre-reduction regime, the sintering time and the cooling rate after sintering, and the effect of vacuum heat treatment. For tensile specimens, in order to obtain an elongation of ≥ 22%, pre-reduction is possible during the 10-minute heating phase. Sintering time to 30 ~ 60min for the best, sintering 2 ~ 3h due to pore polymerization and performance deterioration. Slow cooling is not only necessary during the solidification stage, but also below this stage up to 800 ° C. Using the average cooling rate ~ 50K / min elongation can be obtained ≥ 23%, breaking stress ≥ 1200N / mm ~ 2. Vacuum heat treatment (VHT) can improve the ductility and strength of the sintered samples and reduce their hydrogen content, the most significant effect is for samples quenched from 1400 ℃. The mechanism by which the work is believed to be responsible for cooling sensitivity is hydrogen embrittlement, which results in the brittleness of the quenched specimen. The improvement of ductility by vacuum heat treatment is attributed to the elimination of hydrogen from the intergranular region between the tungsten grains and the matrix.