钼—铼合金的制造及应用

对钼－铼合金的种类、性质、生产技术及应用情况等作了介绍，这对研究铼在钼合金中的作用、机理及开发生产钼－铼合金材料均具一定的参考价值。     

铼的生产与应用研究进展

铼是难熔金属，主要赋存于斑岩铜钼矿床的辉钼矿和黄铜矿中，铼含量在20～2000g／t之间。从钼精矿焙烧产出的烟尘和淋洗液中回收铼及从钼精矿氧压氧化浸出液中回收铼多采用溶剂萃取法和离子交换法。铼用作制取各种催化剂，如汽油重整、烯烃复分解等。铼也用于生产钼铼合金、钨铼合金、镍基超合金和铌铼合金等。铼的某些配合物用作抗癌药物。     

钼-铼合金粉与混合粉烧结后材料的性能对比

重量百分比含铼 4 0 %以上的钼 -铼合金可以承受很大的冷热变化 ,在极端恶劣的环境下钼 -铼合金仍有很长的使用寿命 ,在高温下仍可具有很高的强度 ,可以用作加热材料、热电偶的护套和真空炉用材料等 ,在许多情况下钼 -铼合金是最好的甚至是唯一的选择。但是 ,钼 -铼合金的生产困难 ,现在典型的生产方法是粉末冶金法 ,烧结钼 -铼合金需要的温度很高 ,通常需要在氢气保护气氛中在 2 2 0 0℃的高温下烧结。通过对钼 -铼合金烧结过程的深入理解 ,经过探索简化生产工艺可能降低制造成本 ,本次试验通过烧结钼 -铼合金粉和传统的混合粉制成的试样 ,…     

不同铼含量对钼铼合金性能影响研究概述

钼铼合金因其独特的“铼效应”能够显著改善纯钼的低温脆性,进而使其具有优异的低温加工性能、高温力学性能以及抗辐照性能等。本文总结了铼含量对钼铼合金性能的影响,包括钼铼合金的物理性能、加工性能、力学性能、抗辐照性能、腐蚀性能以及焊接性能;对钼铼合金的研究进行了展望,为未来工艺优化及核电系统的设计选材提供参考。     

钼铼合金板材研究

本文对低铼钼合金板材的加工工艺及合金性能进行了研究。用固液混料方法制取钼铢(Mo-Re)混合粉,用H_2烧结制取Mo-Re合金坯,采用煅造开坯、热轧、冷轧的加工工艺生产0.2mmMo-Re合金板材。M05Re合金抗张强度大于1500MPa,最大负荷为100kg时的杯突深度为0.2mm。钼铼合金的电阻率随铼含量增加有规律地增加。     

钼铼合金的结构和性能

总结了钼铼合金研究的最新进展。典型的钼铼合金成份主要有M041Re，M044.5Re和M047．5Re。钼铼合金坯锭的制备一般采用粉末冶金和真空熔炼的方法。当铼含量低于29％时，铼在钼中固溶形成体心立方结构的α相，钼的晶格常数降低。当铼含量高于29％时，形成x相和σ相。钼铼合金合金的熔点、热性能、电性能介于纯钼和纯铼之间，铼可以提高钼的再结晶温度，降低其塑脆转变温度。铼既可以提高钼的强度，也可以大大改善其塑性。钼铼合金的加工硬化率介于纯钼和纯铼之间而靠近纯钼。     

钨、钼和铼的应用

钨、钼和铼在现代技术中已广泛应用.在国外这些金属的应用构成于70年代末期趋于稳定.钨主要用于硬质合金、特殊钢及合金的生产;钼主要用于钢、铁合金生产中及以化合物形式而得到应用;铼主要用于催化剂及合金的生产(见表).     

超级合金研发现状

评介了超级合金，如钛基合金(钛钼铪合金、钛钼铪铌合金)、镍基合金(镍钼铁合金)、铁基合金(铁钼合金)和钼基合金(钼铼氧化镧、钼铼氧化铈、钼铼氧化钍)等超级合金的研发现状。     

钼铼合金带材的组织和性能

选用熔炼的钼铼合金经过锻造、热拉、冷拉和轧制的方法制备钼铼合金带材，其规格为0．3mm宽0．03mm厚，对其组织和性能进行了研究。结果表明：加工态的拉断力是再结晶状态的2．5倍左右，为24．8N；而延伸率只是再结晶状态的1，3，为3．1％；随着退火温度的提高，钼铼合金的的拉断力直线降低，但延伸率在1723K，30min退火后却最高，金相结果表明1723K退火的钼铼合金带材发生了明显的再结晶。钼铼合金加工态拉伸时其断口表现为准解理断裂，退火后断口表现为明显的韧窝状。铼元素加入钼中，可以提高晶粒和晶粒之间的结合力，使得钼铼合金在拉伸下有很好的延伸率。同时钼铼合金在室温变形时，也容易发生孪晶变形，这一点不同于通常的钼合金。     

Mo-(Re、Y、Zr)合金的制备工艺和性能研究

针对目前医疗行业用钼合金材料的性能要求,通过对钼铼、钼钇、钼锆合金的制备工艺和性能研究,发现3种钼合金都通过第二相细化晶粒,且抗拉强度和屈服强度较纯钼均得到提高,其中钼铼、钼钇合金的塑性下降,钼锆合金的塑性得到提高。综合考虑,钼锆合金有望应用于医疗行业。     

钼-铼-镧合金微观组织及力学性能研究

通过固-液掺杂法在Mo-Re合金中加入稀土La₂O₃纳米颗粒制备得到Mo-Re-La合金, 将Mo-Re-La合金与Mo-Re合金、纯Mo的微观组织及力学性能进行对比研究, 得到如下结论: 在纯Mo中添加低含量Re元素(质量分数3.5%) 对Mo-Re合金有明显的细晶强化效果; 将La₂O₃纳米颗粒加入Mo-Re合金进一步细化和强化了Mo-Re-La合金。     

Structure and hot hardness of RuAl-based alloys produced by reactive sintering using hot isostatic pressing

The structure and hot hardness (at temperatures up to 1100°C) of RuAl-based powder alloys with 1–3 at % Ni, Mo, Re, or Ru are studied. The alloys are produced by the reactive sintering of cold-compacted bars and subsequent threefold isostatic pressing with intermediate annealing at 1500°C performed after the first hot isostatic pressing. The samples have a residual pore content of 1–2.5 vol % and are characterized by a micrononuniform distribution of base and alloying elements. The alloys with refractory metals, such as Re, Mo, or Ru, are found to have the maximum hardness at all temperatures under study. At low temperatures, the effect is more substantial; the hardness of the Re-containing alloys exceeds that of the other alloys by a factor of 1.3–3.6. The increase in the hardness related to solid-solution alloying becomes more substantial owing to the microinhomogeneity of the sintered powder alloys and weakens because of microporosity. Recommendations that allow the uniformity of the distribution of the base and alloying elements to be increased are given.     

Study of the surface properties of nickel-based melts by the constrained drop method: I. Surface tension

The constrained drop method is used to study the surface tension σ of the following melts at 1773–1923 K and p _Ar = 0.1 MPa: nickel of various grades (with various oxygen contents), binary Ni-Al (Re) alloys, and a complex Ni-Re-(W, Mo, Co) alloy. The value of σ of liquid nickel is shown to decrease with increasing oxygen content in it. The additions of aluminum (6%) and rhenium (3–7%) to nickel in binary alloys weakly change its surface tension. Alloying elements (W, Mo, Co) in Ni-Re-(W, Mo, Co) alloys insignificantly affect σ of their melts.     

粉末冶金法制取低铼钼合金的研究

研究了用粉末冶金法制取Mo－3％Re合金的工艺．结果表明．粉末冶金法可以制得性能良好的Mo－3％Re合金．在混和料的制备中采用湿混或干湿混合．有利于Re的均匀分布；且3％Re的加入，可大大细化钼合金的晶粒．     

Influence of Molybdenum and Rhenium Dopants on the Structure and Properties of NiAl–Cr–Co Cast Alloy

Russian Journal of Non-Ferrous Metals - Centrifugal SHS casting has been used for the production of NiAl–Cr–Co–X alloys, where X = 2.5–15.0 wt % Mo and up to 1.5 wt % Re....     

A castability model based on elemental solid-liquid partitioning in advanced nickel-base single-crystal superalloys

A castability model that accounts for the characteristic segregation behavior of constituent elements in Ni-base superalloys has been developed and experimentally verified in production scale casting trials. The model ranks alloy compositions with respect to their susceptibility to freckle formation during directional solidification. Thirty-nine distinct Ni-base single-crystal superalloys encompassing a broad range of compositions were investigated to assess the influence of the constituent elements on their solidification characteristics. Linear regression was applied to the fitted solid-liquid partition coefficients of the major constituent elements to develop formulas capable of describing elemental interactions. The high-density refractory elements Ta, W, and Re were found to segregate most severely during solidification. Increasing the amount of Cr and Mo in high-refractory single-crystal alloys reduced the extent of W and Re microsegregation during solidification. This effect was found to minimize the occurrence of freckle defects due to the corresponding decrease in the density inversion term, which is effectively the driving force for thermosolutal convective instabilities known to cause macroscopic grain defects during single-crystal solidification. Model predictions were validated using production scale casting trials where additions of 1.5 wt pct (1.9 at. pct) Cr and 3.0 wt pct (2.0 at. pct) Mo to a high-refractory superalloy more than halved the number of solidification-related grain defects formed. These findings suggest that elemental interactions between Cr, Mo, W, and Re need to be considered when optimizing alloys for high-temperature creep properties.     

Composition effects on mechanical properties of HFC-strengthened molybdenum alloys

The mechanical properties of swaged rod thermomechanically processed from arc-melted Mo-2Re-Hf-C alloys containing as much as 0.9 mol pct HfC have been evaluated. The low temperature ductilities of these alloys were not influenced by the amount of HfC present but by the amount of Hf in excess of stoichiometry. Maximum ductility occurred at 0.2 to 0.3 at. pct excess Hf. At 0.3 to 0.5 mol pct HfC, alloy strength varied directly with the Mo content of extracted carbide particles, both decreasing as the amount of excess Hf increased. Additions of 2 at. pct Re had little effect on strength or ductility. Tensile and creep strengths of Mo-2Re-0.7Hf-0.5C alloy equaled or exceeded those of other high strength Mo alloys.     

Composition effects on mechanical properties of HFC-strengthened molybdenum alloys

The mechanical properties of swaged rod thermomechanically processed from arc-melted Mo-2Re-Hf-C alloys containing as much as 0.9 mol pct HfC have been evaluated. The low temperature ductilities of these alloys were not influenced by the amount of HfC present but by the amount of Hf in excess of stoichiometry. Maximum ductility occurred at 0.2 to 0.3 at. pct excess Hf. At 0.3 to 0.5 mol pct HfC, alloy strength varied directly with the Mo content of extracted carbide particles, both decreasing as the amount of excess Hf increased. Additions of 2 at. pct Re had little effect on strength or ductility. Tensile and creep strengths of Mo-2Re-0.7Hf-0.5C alloy equaled or exceeded those of other high strength Mo alloys.     

热压法制备的(Mo1-xMbx)5Si3合金组织及抗腐蚀性能

以Mo粉、Nb粉、Si粉为原料,采用热压法制备(Mo<,1-x>Mb<,x>)<,5>Si<,3>(x=0,0.2,0.4)难熔金属硅化物合金,利用电化学测试及盐酸浸泡腐蚀实验,研究该合金在浓度为1 mol/L的HCl溶液中的腐蚀行为以及Nb含量对合金组织和耐蚀性的影响.结果表明,随Nb含量增加,(Mo<,1-x>Mb...     

Ductility and impact resistance of powder-metallurgical molybdenum-rhenium alloys

Mo-Re alloys containing between 5 and 47.5 wt pct Re were fabricated from Mo and Mo-Re powders by sintering and hot radial forging. The mechanical properties of as-forged, stress-relieved, and recrystallized specimens were examined. Up to a concentration of 41 wt pct Re, the Charpy ductile-to-brittle transition temperature decreased monotonically with increasing rhenium concentration. Consistent with this, bend angles for fracture at T=−100 °C increased monotonically with increasing rhenium concentration. Between 10 and 41 wt pct rhenium, the room-temperature tensile ductility of recrystallized Mo-Re remained nearly constant with values on the order of 35 to 45 pct. This result differs from the low ductility values observed previously by Lundberg (1997) for compositions on either side of Mo-13 wt pct Re.