(中南大學 材料科學與工程學院，長沙 410083)
摘 要: 利用彎曲性能測量、金相、SEM觀察和EDS分析等方法，對不同C含量的Mo-C棒橫向彎曲性能及組織進行研究。結(jié)果表明：1號Mo-C棒中C含量(摩爾分數(shù))為290×10−6，O含量為25×10−6，2號Mo-C棒中C含量為150×10−6，O含量為25×10−6；在同樣條件下，2號Mo-C棒的橫向彎曲性能更好；2號Mo-C棒的再結(jié)晶溫度為950~1 100 ℃左右；隨著退火溫度的升高，合金的橫向彎曲性能逐漸提高，在1 100 ℃時，合金的橫向彎曲伸長率最高，達到10%；純鉬的斷裂方式以沿晶斷裂為主，添加C后，合金的裂紋擴展應(yīng)力得到提高，合金的斷裂方式變成以穿晶斷裂為主，斷口上有大量的解理面，具有明顯的河流狀花樣和解理臺階；當添加的C含量偏高時，合金中生成大顆粒的碳化物，這種大顆粒的碳化物降低了合金的塑性。
關(guān)鍵字: Mo-C棒；橫向塑性；沿晶斷裂；穿晶斷裂
molybdenum-carbon bars
（School of Materials Science and Engineering, Central South University, Changsha 410083, China）
Abstract: The transversal bending property and microstructure of molybdenum-carbon bars under different conditions were investigated by bending property measurement, optical microscopy, scanning electron microscopy and EDS. The results show that the molar fractions of C and O in Mo-C bar No.1 are 290×10−6 and 25×10−6, respectively, and those in Mo-C bar No.2 are 150×10−6 and 25×10−6, respectively. The transversal bending property of Mo-C bar No.2 is better than that of Mo-C bar No.1 under the same condition. The recrystallization temperature of Mo-C bar No.2 is 950−1 100 ℃ and during the annealing process, the transversal bending property is gradually improved and the elongation of the transversal bending reaches a maximal value of 10% at 1 100 ℃. The fracture type of pure Mo is intergranular fracture, the enhancement of the crack propagation stress of the Mo-C alloy is due to the addition of carbon, which makes the fracture type change to a transgranular fracture type. A large number of cleavage planes and steps are observed on the bending fracture surface. But if the carbon content is too high, the carbide precipitation will be severe at grain boundaries and decrease to the ductility of the alloy.
Key words: Mo-C bars; transversal plasticity; intergranular fracture; transgranular fracture
