较为详细地介绍了钨元素的发现历程,钨金属与合金、含钨杂多配合物、氧化钨、碳化钨、钨硫族化合物和合有W-W四重键的化合物的应用.

Effect of tempering temperature between 400℃ and 700℃ on microstructure and carbide transformation of H13 steel was studied by means of mechanical property test and microstructure and second phase analysis. The results indicate that when tempered at 400-450 ℃, microstructure of the quenched H13 steel is characterized by tempered martensite, and the carbides mainly consist of VC and Fe3 M3 C. The hardness peak of the steel can be observed when tempered at 550 ℃, because of secondary hardening effect caused by a large number of Mo2 C precipitate. When tempered at 600-650℃, the martensite decomposes substantially, the size of carbides grow gradually, the hardness decreases sharply and the toughness grows quickly. The microstructure becomes tempered troostite, and the primary carbides are Fe3 M3 C, Cr7 C3 and VC while tempered at 650 ℃. When tempered at 700 ℃, the H13 steel shows overaging phenomenon as the matrix becomes tempered sorbite, and the dimension of carbides increase significantly.

Effect of niobium on microstructure and hardness of spray formed M3∶2 high speed steel was investigated. And the wear behavior of M3∶2 high speed steel with Nb at different temperature is also discussed.The results show that the addition of niobium can make MC carbides smaller and more spherical, and M2 C lamellar more thinner, which is helpful for secondary precipitation of high speed steel during tempering and improving the hardness after tempering.With the temperature increased, the M3-0.5Nb high speed steel presents better wear resistance than that of the M3 steel.Wear mechanism of the high speed steels is depends on the temperature.At room temperature, abrasive wear dominates;near 300℃, it transfer to adhesive wear, and the oxidation wear gradually increases.At higher temperature, near 500℃, the wear mechanism is oxidation wear accompanied with some abrasive wear and adhesive wear.

Ignition-combustion test was carried out and the combustion samples of GH4169 and GH4202 superalloys were ana-lyzed by using optical microscopy, scanning electron microscopy and energy dispersive spectrometry. A model of mass transfer, heat transfer and oxygen transfer was built to analyze the combustion mechanism of the alloys. Some methods to improve the ability of com-bustion resistance for new superalloys were proposed. The results show that both the alloys burn in the test condition, but GH4202 per-forms better than GH4169. Both the alloys burn in liquid phase, there is a combustion section composed of oxides and metal particles in front of the reaction zone, and the burning behavior of elements in the combustion section decides the combustion ability of the whole alloys. A selective combustion rule of elements is present in the combustion section, the elements such as Nb, Ti, Al and Cr will burn with oxygen easily, while Ni is of delayed combust with low heat and can protect the alloy from combustion.

通过真空感应熔炼、锻造及热处理等工艺,制备了Fe-17 mass％ Mn减振合金,采用热膨胀法测量材料的相变点,并进行组织观察和分析.在不同温度和应变条件下,测试了材料的阻尼性能,并分析其振幅内耗效应.结果表明,实验合金在低温低应变振幅下表现出反常振幅效应,在高温高应变振幅下出现振幅内耗峰.由于溶质原子在不同温度下的动性不同,位错在不同振幅下的运动速度不同,以及溶质原子和位错线之间的"跟、拖、甩"作用等,可将G-L模型中的钉扎点看成可动的,来解释此情况.

30SiMn2MoVA钢作为我国传统轻武器身管用钢,逐渐不能满足现代武器的要求,内膛镀铬处理带来的问题也急需解决.选用一种新研发的具有良好室温、高温和低温强韧性匹配的热模钢25Cr3Mo2NiSiWVNb,结合其合金元素种类,通过盐浴渗氮进行表面改性,并与30SiMn2MoVA镀铬进行比较.开展了30SiMn2MoVA镀铬和热模钢渗氮后组织形貌观察、硬度检测以及热模钢渗氮前后物相变化的分析,并针对身管储存要求及实际射击工况,对两种试样的耐蚀性和耐高温磨损性能进行比较.结果表明:热模钢渗氮后硬度高于镀铬层,在3.5％ NaCl溶液中耐腐蚀性能与镀铬层相当,但是耐高温磨性能仍需要进一步提升.

采用扫描电镜观察H13钢不同退火条件退火过程中残留碳化物及退火组织中碳化物形态与分布特征,利用图像处理软件定量分析了碳化物数量、体积分数及大小,并研究了不同退火条件对其相应的回火态力学性能的影响.结果表明,H13钢缓慢冷却退火,选择Ac1～Ac3温度区间短时保温,可获得均匀分布的细小球状残留碳化物,在退火时即使冷却速度较快也可获得球状碳化物均匀分布的退火组织,并保持较好的力学性能.

The high-speed steels W6Mo5Cr4V2 containing Nb(M2-Nb) were produced by traditional casting and spray-forming,respectively.According to the relationship between room temperature hardness and microstructure of the two forged alloys after heat treatment,the optimum quenching and tempering temperatures were obtained for the two high-speed steels.Then,the elevated temperature properties of the two kinds of high-speed steels were analyzed in optimum heat treatment conditions.The results show that the microstructure of as-deposited billet of the spray-forming M2-Nb high speed steel is composed of fine equiaxed grains,and the carbides are uniformly distributed along grain boundaries.After quenching at 1180 ℃ and tempering at 560 ℃ for three times,the hardness of forged spray-forming M2-Nb high speed steel is 2.6 HRC higher than that of the forged as-cast high speed steel under its optimum heat-treatment condition.In addition,the red-hardness and high temperature hardness of the forged spray-forming high speed steel are also higher than that of the forged as-cast one.