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 回顾了无塑性转变温度落锤试验和落锤撕裂试验2种试验方法的建立,对落锤试验和落锤撕裂试验的区别以及在不同领域的应用做了论述,为材料的试验研究提供参考依据。此外,对落锤试验机以及试验实例进行简要介绍,为落锤试验厂家研制试验机提供一些建议。     

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 本文提出了一种基于直接冲击电压对电器绕组匝间绝缘的试验方法。用电压波形比较法，把冲击电压经高速切换，交替施加于被测绕阻两端和参考物绕组两端，通过观察电压衰减振荡波形的变化，便可检测被测绕组的匝间是否有异常。     

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以IF钢和高强IF钢为试验材料,讨论了现行二次加工脆化试验方法中存在的问题。研究认为,模具间隙影响试验结果的真实性,锤头与样杯同轴度严重影响试验结果的有效性,然而现行标准中却没有对模具及锤头与样杯同轴度提出要求。     

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 材料的疲劳过程是能量耗散的过程,在宏观上表现为热耗散,能量理论是研究材料疲劳行为微观机理和宏观现象的桥梁。文中利用红外热像仪对具有颈缩部分的45号钢试件疲劳过程中的温度变化进行了研究,探讨了影响温度变化的机制,并介绍了快速确定45号钢疲劳极限的方法。实验结果表明,该方法所测得的疲劳极限合理,且该方法具有非接触、便捷、低成本等优点。     

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 物理检测中常发现试样有不同程度变形,主要有弯曲与扭转变形,严重影响试样物理性能的准确性。文章对宽带试样变形的产生原因及试样变形对物理性能的影响进行了分析。     

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采用金相显微镜、扫描电镜分析了全淬透钢轴承套圈在磨加工后表面出现的裂纹,经高倍分析缺陷处无明显脱碳,经能谱及电镜面扫描分析裂纹内主要元素为氧、铝、钙、锰等元素,且以氧、铝元素为主,其直接原因为夹杂物造成材料宏观裂纹;经讨论脆性夹杂物将严重影响轴承的使用精度及寿命,对该批材料进行全部报废处理.     

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 无取向电工钢W800基板在热连轧轧制过程中板面出现凹坑和孔洞质量缺陷,采用化学成分检测和金相微观组织分析法进行了系列分析。结果表明,该类热轧基板的凹坑缺陷是由于板带轧制时撞击和磨擦精轧机组的侧导板,生成了不少外部异物,飞落到板带板面,经后续轧制压入板带表面,然后又脱落形成板面凹坑;由于带钢频繁撞击侧导板,导致板带边部形成裂口,同时侧导板局部断裂成小块,并压入带钢,经后续轧制时,因形变不一致生成了孔洞缺陷。     

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 普通金相浸蚀方法观察材料的显微组织虽然简洁快速,但它往往只能显示晶界和相界,并且难以有效地区分多于两相的显微组织。特别是低碳贝氏体复相钢组织比较复杂,普通金相浸蚀方法很难满足需要,运用彩色金相技术和电子背散射（Electron Back Scatter Diffraction, EBSD）技术对低碳贝氏体复相热轧钢板产品的显微组织进行相鉴别的研究鲜见报道,笔者在各相定量分析方面进行了一些尝试和探索,并取得了一系列成果和进展。     

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 研究了非晶丝材磁致伸缩系数的小角转动测量方法，采用小角转动法(SAMR)测量了Co69.9Si12.5B9Fe5Cr3.5Mo0.1非晶合金丝感应电压的二次谐波信号随直流偏磁场、应力及驱动电流的变化关系，通过对测量条件的优化，测量了非晶丝感生各向异性场随应力的变化关系。得到Co69.9Si12.5B9Fe5Cr3.5Mo0.1非晶丝的磁致伸缩系数λs为1′10-7。     

磷含量对IN718合金持久和蠕变性能的影响

研究了不同含量的磷在ＩＮ７１８合金的作用。结果表明,磷对持久和蠕变性能有显著的影响,可提高ＩＮ７１８合金晶界抗蠕变形裂的能力,将磷含帅０．００３％提高至０．０３％,持久寿命先是增加而后降低,并在含磷０．０２５％年达到持久寿命峰值。磷对应力指数影响不大,但对表观蠕变激活能影响显著。磷的有益作用主要来自于抑制晶界扩散和改善晶界δ相。     

正火冷速对2.25Cr-1Mo钢持久性能的影响

采用SEM、持久性能测试等手段,研究了不同正火冷速对2.25Cr-1Mo钢持久性能的影响。结果表明:当采用空冷、30 ℃/min、5 ℃/min冷却时,2.25Cr-1Mo钢在530 ℃的外推持久强度σ₁₀⁴均为120 MPa左右。当正火冷速降至1 ℃/min时,持久性能显著降低,主要因为此时在贝氏体-铁素体界面析出大量大颗粒析出物,导致蠕变孔洞产生;同时大量的先共析铁素体出现,基体强度降低,难以阻碍持久裂纹扩展,导致持久性能下降。     

Effect of surface recrystallization on the creep rupture property of a single-crystal superalloy

The effect of surface recrystallization by heating after shot-peening on the creep rupture property and fracture behavior of a single-crystal superalloy was investigated. The results show that the creep rupture property of the single-crystal superalloy was greatly influenced by surface recrystallization. A recrystallized surface layer with a depth of 101 μm resulted in a decrease in creep rupture life by nearly 50%, and an almost linear reduction of creep rupture life was observed with the increase of recrystallization depth. A lower strength of the recrystallized layer, inhomogeneous deformation between the recrystallized layer and the matrix, and stress concentration caused by notch effect resulted in the decrease in creep rupture life of the single-crystal superalloy.     

Evaluation of creep rupture behaviour for weld joint and base metal of the Cr35Ni45Nb alloy

In order to investigate microstructure and creep rupture strength of a weld joint after aging, Cr35Ni45Nb alloy tubes were welded by the GTAW process of two-type filler metals. The tensile test, hardness and creep test were conducted to analyse the mechanical properties of the weld joint and base metal. The results show that the creep rupture time of the base metal at 1373?K is longer than a new weld joint, while the tensile properties of the base metal at room temperature are similar to a new weld joint. With aging, the microstructure of the weld metal and the base metal tended to be homogeneous, the creep rupture time of the weld joint improved and was similar to that of the base metal.     

金属拉伸试样原始力学性能测量的讨论

金属拉伸力学性能因拉伸温度和拉伸速率的改变引起测试不确定性,导致在一个温度一个应变速率下的拉伸试验结果,一般不是被测金属的原始力学性能.拉伸试验新技术体系表明,越快的拉伸应变速率,"力学性能-拉伸应变速率"曲线上的力学性能越接近原始力学性能.存在充分快的拉伸应变速率,在"力学性能-拉伸应变速率"曲线上能获得原始力学性能...     

Research on the creep damage and interfacial failure of dissimilarmetal welded joint between 10Cr9Mo1 VNbN and 12Cr1MoV steel

0　IntroductionAnewmodified 9Cr Mosteel (SA2 13T91orT91)pos sessesimprovedhightemperaturestrength ,excellentductili ty ,weldability ,heatfatigueproperties .Therefore ,T91hasbeenwidelyusedinelectricpower,petrochemicalplant,nu clearpowerstation ,andsoon[1～3] .Itisappliedtothefinalstagesofsuperheatersandreheatersinfossil firedpowerplants .However,lowalloypearlitesteel(12Cr1MoV)isstillusedintheearlierstages .Thus,therearealotofdissimilarmetalweldedjoints (DMWJs)betweenSA2 13T91and12Cr1Mo…     

澳标与国标夏比V型缺口冲击试验标准的比较

主要介绍钢材检验中必不可少的夏比V型冲击试验,从试样装置、试样条件、试样样品、试验要点等方面对澳洲标准AS 1544.2-2003进行了详细地解读,并将现行的国家标准GB/T 229－2007、澳洲标准AS 1544.2-2003中相同和不同之处做了对比探讨,以深刻了解和认知澳洲针对材料进口的检测要求,从而增加出口检验合格率。     

铌含量对S31042耐热钢析出相及持久性能的影响

以高、中、低3种铌含量的S31042耐热钢作为试验钢,研究了铌含量对S31042钢中析出相及持久性能的影响。结果表明： S31042钢时效处理后,钢中主要含有M23C6相、Z相和MX相;当时效时间达到10 000 h时,钢中发现了σ相的存在。铌含量对S31042钢中析出相的种类和M23C6相的含量影响不大,对含铌相含量的影响显著,随着铌含量的升高,Z相+MX相含量明显增多。700 ℃持久寿命并未随铌含量的升高而单调增加,而在中限铌含量出现最大值,高铌钢中未固溶的粗大一次析出相是造成持久寿命降低的主要原因。     

Effect of si addition on mechanical alloying behavior and creep properties of Al-10Ti-xSi alloys

Al-10Ti-xSi alloys (x=0∼6wt.%) have been mechanically alloyed under Ar atmosphere using an attritor and the alloying process has been investigated. From Al-10Ti composite powders, supersaturated Al(Ti) powders were obtained after mechanical alloying. In the ternary mixture, fine Si particles were observed to be distributed in the Al(Ti) matrix due to both the negligible solid solubility of Si in the Al matrix and the weaker chemical interaction of Si with Al, as compared with Ti. The sealed compacts were hot extruded to full density at 450°C with an extrusion ratio of 12:1. The microstructures and creep properties of the hot extruded alloys were examined. During consolidation, Si particles were dissolved in Al₃Ti up to 4 wt.% Si to form the (Al(Si))₃Ti phase, and the Ti₇Al₅Si₁₂ phase was formed beyond the solubility limit of Si in Al₃Ti. The transition from the Coble creep mechanism at low stresses and temperatures to dislocation one at high stresses and temperatures was observed. The stress and temperature of the transition from diffusional to dislocation creep became higher as Si concentration increased. This was due to an enhancement of Al₃Ti particle strength with increasing Si content as a result of Si incorporation. Thus, the addition of Si enhances the creep resistance of the MA Al-10Ti alloy.