Experience of Application of EBW in Producing Welded VT41 Alloy Drums in the Design of an HPC in an Advanced Engine

The conditions of electron-beam welding (EBW) of ring samples made of a VT41 alloy are adjusted to produce large welded joints of this alloy for a high-pressure compressor (HPC) of an advanced engine. The problems of quality control of a welded joint, the level of residual stresses in the near-weld zone, the microstructure of the welded joint, and its properties are considered.     

固溶处理对690镍基合金组织和力学性能的影响

研究了1050～1150℃固溶处理对20 kg真空感应炉熔炼的690镍基合金(%:0.020C、29.93Cr、9.82Fe、0.19Al、0.25 Ti、0.023Nb、0.012Mo、0.004 2N)1.0mm冷轧板的组织和力学性能的影响。结果表明,当固溶温度从1050℃提高至1100℃,平均晶粒尺寸呈线性增长,从12μm提高到29μm,超过1100℃时晶粒尺寸快速增长,1150℃时平均晶粒尺寸达58μm;1090℃以上固溶处理时,合金中富铬碳化物完全溶解;690镍基合金主要强化机制为细晶强化,随固溶温度升高,合金室温抗拉和屈服强度分别从780 MPa和400 MPa降至662.5 MPa和250MPa,伸长率由40%提高至51.75%。     

固溶处理对GH4700镍基合金管组织及力学性能的影响

研究了1 000～1 150℃固溶处理对GH4700合金(/%:0.05C、25Cr、20Co、1.65Nb、1.47Al、1.69Ti,余Ni)组织及力学性能的影响:结果表明,1 180℃挤压空冷后Φ89 mm×15 mm GH4700管材的抗拉、屈服强度和伸长率分别为1 150 MPa、780 MPa和36%;合金在1 000～1 060℃固溶处理,随着温度的提高,γ’相逐渐溶入基体,合金晶粒明显长大,强度显著降低,塑性显著升高;在1 090～1 150℃随着温度的提高,晶粒长大趋势不明显,合金强度和塑性的变化趋势放缓。1 150℃固溶处理后GH4700合金抗拉强度800 MPa,屈服强度330 MPa,伸长率65%。     

Effect of Boron Addition and Initial Heat-Treatment Temperature on Microstructure and Mechanical Properties of Modified 9Cr-1Mo Steels Under Different Heat-Treatment Conditions

The effect of initial heat treatment on microstructure and mechanical properties of boron-free and boron-containing modified 9Cr-1Mo steel (P91 and P91B, respectively) has been studied under different heat-treatment conditions. The prior austenite grains evolved in P91 steel, having different prior austenite grain sizes, were found to be similar in size after heat treatment in the range of 1073 K to 1448 K (800 °C to 1175 °C) for 5 minutes. The microstructural evolution in P91B steel having different prior austenite grain sizes appeared to be uniform when subjected to different heat-treatment temperatures with the prior austenite grain size being similar to that of initial grain size. Lath martensite was observed in P91B steel after all heat treatments. On the other hand, lath martensite was observed in P91 steel only when subjected to high-temperature heat treatment, whereas subgrain/substructure as well as coarse precipitates were observed after a lower temperature heat treatment. Large differences in the hardness/strength values between different microstructures corresponding to coarse-grained heat-affected zone (CGHAZ) and intercritical HAZ (ICHAZ) of P91 steel weldment were due to the distinct difference in these microstructures. The difference in hardness/strength values between the CGHAZ and ICHAZ was found to be insignificant in P91B steel under similar heat-treatment conditions.     

Effect of GTAW Parameters on Structure and Mechanical Properties of C86300 Weld Joint

In this study, the effects of heat input variation in gas tungsten arc welding (GTAW), on structure and mechanical properties of commercially C86300 (containing addition of 0.6 wt% silicon) weld joint were investigated. Following microstructural characterization of Base metal, GTAW has been performed at welding currents 50 and 60 A and flow rates of argon shielding gas (10, 14 and 18 l/min) using the same filler metal composition. Therefore six GTAW samples were performed with various welding specifications. By structural investigations and hardness profiles, effects of increasing heat input on increasing average grain size in weld zone, heat affected zone width, penetration depth and alloying element losses were indicated. However increasing heat input increases penetration depth and has a positive effect on hardness and strength of the joint. In considering wear application of this alloy castings and probable GTAW for them, pin-on-disc wear test was performed and revealed better wear resistance of weld metal in comparison with base metal. Hence the optimum values of welding current and argon flow rates (in GTAW with the same composition filler) was determined for this alloy.     

钛含量对Inconel 690镍基合金力学性能的影响

研究了Ti含量(0.35%～1.10%)对Inconel 690镍基合金(%:0.034～0.036C、29.40～29.68Cr、9.11～9.22Fe、0.34～0.36A1、0.004 4～0.004 5N)950～1 100℃水冷+715℃15～100 h空冷后的室温和350℃的组织和力学性能。结果表明,含1.10%Ti合金的强度(Rm和Rp0.2)较含0.35%～0.70%Ti合金的强度高200～400 MPa,强度提高的主要原因为715℃时效后1.10%Ti合金析出3.70%～3.99%γ′强化相,而0.35%～0.70%Ti合金715℃时效后γ′强化相析出量仅为0～0.53%。     

铌对新型Ni-Cr-Fe镍基合金力学性能的影响

新型Ni-Cr-Fe镍基合金(%:0.036～0.044C、16.71～17.10Cr、63.04～63.95 Ni、8.98～10.76Fe、2.50～2.88Mo、2.01～4.97Nb、0.06V、0.74～0.82Al、2.00～2.06 Ti)由25 kg真空感应炉熔炼,锻成Φ15 mm和14mm×14 mm棒材。采用扫描电镜(SEM),X射线衍射仪(XRD),化学相分析和拉力试验研究了铌含量对65Ni18Cr-10Fe合金组织和性能的影响。结果发现,随着合金中铌含量的增加,γ′、γ″、η相的析出数量增多,尺寸增大,形态由断续的颗粒、短棒状改变为长片层状;导致合金的室温强度随之升高,而塑性随之下降。     

Effect of Metal-Powder Composition Fraction and Layer Thickness on Structure and Mechanical Properties of Alloy VT6 Synthesized Material Prepared by Selective Laser Melting

Metallurgist - This article considers questions of the effect of layer thickness during synthesis of alloy VT6 material by selective laser melting and use of a metal powder composition with a size...     

The Effect of Morphology and Particle-Size Distribution of VT20 Titanium Alloy Powders on the Mechanical Properties of Deposited Coatings

Powder Metallurgy and Metal Ceramics - The surface morphology of coatings produced from spherical and nonspherical VT20 titanium alloy powders with different particle-size distributions has been...     

添加钨对USC141镍基合金力学性能的影响简

 参照USC 141镍基合金的化学成分，进行了热力学模拟计算。计算结果表明：钨能提高M23C6和M6C的? 湮露龋⒋俳谩湎嗪蚆6C的析出。在USC 141化学成分基础上，添加钨元素取代部分钼元素，设计了一种试验型镍基合金(HR100)。通过室、高温力学性能测试、持久试验和析出相分析，对其力学性能和析出相进行了研究。试验结果表明：经相同热处理后，试验型镍基合金HR100中的γ′相和M6C的析出明显多于USC 141，使其室温综合力学性能、高温强度以及持久寿命均明显优于USC 141，但同时大量析出的M6C会降低其高温和持久塑性。通过调整钨和钼的含量来调节M6C相的析出量，可以作为一种提高USC 141室、高温综合性能的方法。     

热处理温度对高强变形铝青铜的组织和力学性能的影响

针对一种新型高强变形铝青铜合金,考察了淬火温度和回火温度对该合金的微观组织和力学性能的影响。研究结果表明,淬火温度越高,合金内部的β'马氏体相越多,材料的硬度越高,但淬火温度过高时,由于针片状α相的出现,使材料的强度和塑性有较大下降。试验合金适宜的淬火温度为900℃。淬火态材料经低温回火,强度可进一步提高,400℃回火时材料的强度和硬度达到峰值,此后随着回火温度的升高,材料的强度和硬度逐渐下降,延伸率逐渐提高。600℃回火态材料的抗拉强度和延伸率分别达到900 MPa和17%以上,具有优良的强韧配合。     

Mechanical Properties and Microstructural Characterization of Aged Nickel-based Alloy 625 Weld Metal

Metallurgical and Materials Transactions A - The aim of this work was to evaluate the different phases formed during solidification and after thermal aging of the as-welded 625 nickel-based alloy,...     

Role of Mg on Structure and Mechanical Properties in Alloy 718

The role of Mg in alloy/718 has been systematically investigated. Mg raises not only high temperature tensile and stress-rupture ductilities but also increases considerably smooth and notch stress-rupture life. Mg containing alloy 718M is free of stress-rupture notch sensitivity. Mg improves creep and fatigue interaction properties （LCF or cyclic stress rupture） at any grain size. The basic role of Mg is equilibrium segregation at grain boundaries which helps to change continuous grain beundary (5-Ni3Nb morphology to discrete globular form which has a retardation effect on intergranular fracture. Mg promotes the change from intergranular to transgranular fracture mode.     

Forecasting Mechanical Properties of Forgings of VT6 and VT3-1 Titanium Alloys Depending on the Chemical Composition and Structure

The statistical dependences of the mechanical properties of 218 forgings (15 dimension types) made of VT3-1 and VT6 alloys in 2000–2014 on the chemical composition (content of alloying elements and impurities and structural and strength aluminum and molybdenum equivalents), type, subtype, and structural parameters after annealing, quenching, and aging are investigated. It is established that the strength and plastic properties of single-type forgings vary rather widely. The part of the variation in the forging properties caused by fluctuations of the content of major components and impurities, as well as by the influence of the structural type and sizes of structural components, is evaluated. It is revealed based on correlation analysis that the variation in amounts of each alloying element and impurity has little or no effect on the forging properties. This is caused by small fluctuation intervals of their concentrations in the limits of the grade composition. However, their total content expressed through aluminum and molybdenum equivalents can vary in a rather wide range. It is statistically substantiated that the part of the variation in the tensile strength of forgings of VT3-1 and VT6 alloys caused by the influence of the chemical composition (recalculated to aluminum and molybdenum equivalents) may be ～25–65%, while that caused by the influence of the structural type and subtype is about 20%. The part of the variation under the joint effect of these two factors (composition + structure) can reach ～50–65%. This index for plasticity and impact toughness is smaller and lies in a range of 20–35%. Mathematical models for forecasting the mechanical properties of forgings depending on the structural parameters and aluminum and molybdenum equivalents are proposed.     

固溶时效对TC4合金组织与机械性能的影响

研究了固溶时效对TC4合金的显微组织、室温力学性能、硬度、冲击韧性的影响。结果表明,经过α＋β区固溶处理＋530~760℃时效处理后的TC4合金显微组织分别为球状或条状初生α和转变β基体,随时效温度的提高,室温强度和硬度降低,塑性和冲击韧性无明显变化;β区固溶处理＋530℃时效处理后的TC4合金显微组织分别为魏氏组织和马氏体。     

不同热处理工艺对工业TC4合金板材组织和性能的影响

研究了两相区普通热处理和β相区固溶+两相区固溶双重热处理对工业TC4合金板材组织和性能的影响。结果表明:两相区普通退火处理(分别在700,750,800℃保温1 h,空冷)可以得到较好的综合性能,随温度升高,晶粒略有长大,强度、塑性逐渐降低;β相区固溶+两相区固溶双重热处理(1 050℃×30 min,AC+720℃×2 h,AC)得到网篮组织,强度、塑性明显降低。     

烧结温度对内燃机用TiZrVMo高熔合金组织和力学性能的影响

运用放电等离子烧结方法(SPS)制备TiZrVMo合金,并通过控制不同的烧结温度获得了不同力学特性与组织结构的试样。测试结果表明,对合金烧结处理后其基体中形成了包含BCC与FCC两种晶体结构,BCC组织形成了比FCC组织更高的衍射峰。当烧结温度增加后,晶粒尺寸呈现增大的现象,塑性先增大后降低。经过1100℃烧结得到的试样压缩屈服强度为1501.4MPa,塑性应变31.4%。随着烧结温度的增加,屈服强度先减少后增加,塑性应变先增大后减小。当烧结温度上升后,合金材料从准脆性断裂逐渐转变为微孔聚集型断裂,之后形成了大尺寸晶粒并发生沿晶断裂的现象,呈现脆性解理断裂的特点。