燃气轮机隔热板GH22合金的组织和力学性能

采用真空感应熔炼的方法制备GH22母合金,然后真空感应重熔浇注成等轴晶成形试棒,测试其室温拉伸、高温拉伸和持久性能.利用熔模失蜡精密铸造技术生产了重型燃机GH22隔热板铸件,对隔热板不同部位进行了宏观晶粒度、光学金相、扫描电镜及能谱分析.从国产、进口隔热板底板分别取样加工成力学性能试样,进行了室温拉伸、高温拉伸和高温持久性能测试.结果表明:国产GH22母合金的成分和性能满足要求.国产铸件取样试样的宏观晶粒度、室温拉伸、高温拉伸性能与国外铸件相当.国产铸件具有更高的高温持久强度,这主要是由于国产GH22母合金中碳含量更高,合金组织中在枝晶间和晶界处析出更多的碳化物相.     

V元素对铁镍基变形高温合金GH4061组织和性能的影响

采用金相显微镜(OM)、扫描电镜(SEM)、透射电镜(TEM)和电化学萃取相分析等手段,研究了V元素对GH4061合金晶粒度、碳化物和γ?/γ"强化相等影响,测试了不同V含量试样的室温和750℃拉伸性能以及750℃/460 MPa持久性能,分析了V元素对合金显微组织和力学性能的影响。结果表明：GH4061合金中添加V元素促进了MC型碳化物和γ?/γ"相析出,使晶粒尺寸小幅减小;V元素通过增大γ基体的晶格常数,降低γ基体与γ?相的错配度,抑制了γ?/γ"相在750℃的快速粗化;V元素添加对室温拉伸性能影响不大,但可显著提升750℃拉伸强度和持久寿命;当V含量为0.4%(质量分数)时,GH4061合金具有最佳的750℃持久性能。     

C和B的含量对K417G镍基高温合金的凝固行为和高温持久性能的影响

对不同C、B含量的K417G合金进行DTA分析、等温淬火实验和950℃/235 MPa持久性能测试,并观察其组织形貌,研究了C、B含量对K417G镍基高温合金的凝固行为和高温持久性能的影响。结果表明,在合金的凝固期间C含量影响碳化物的析出温度和初生碳化物的含量,且随着C含量的提高而提高;共晶组织的析出温度主要受B元素含量影响,且共晶含量随着B含量的提高而提高。合金在950℃/235MPa条件下持久变形期间其断裂机制为裂纹在晶界处萌生并沿晶界扩展,晶界处的MC型碳化物分解成富Cr的M₂₃C₆型碳化物而使晶界的稳定性降低;在合金成分范围内提高B元素含量能改善合金在高温变形期间的晶界强度,因此适当降低合金中的C含量和提高B含量有助于改善合金的高温持久性能。     

GH141合金的高温拉伸及持久性能

研究了热处理对GHl41合金760℃拉伸及900℃／170MPa持久性能的影响及合金显微组织与高温力学性能之间的关系。结果表明，GH141合金的760℃屈服强度σ0.2^760与晶粒平均直径D之间仍符合Hall—Petch关系；γ′强化机制可用位错切绕转换模型描述；晶界碳化物的种类、数量和尺寸对合金的持久寿命影响显著；晶内强度与晶界强度的合理匹配也是获得高持久寿命的重要因素。     

影响单晶Ni基高温合金持久性能的因素

本文研究了一些直接影响单晶 Ni 基高温合金持久强度的因素。原始晶界和由机械加工引起的再结晶对性能的危害极大。在经高温持久试验后的单晶中,往往形成亚结构和微孪晶。单晶合金的[001]方向平行应力轴时,持久性能最佳。当[001]方向与应力轴夹角大于10°时,持久强度大幅度下降。单晶合金中碳化物的含量越多,尺寸越大,对持久性能损害越大。初生γ′和共晶相区是单晶合金中的低强度区域,应通过固溶热处理消除。单晶高温合金经组织结构和晶体取向的一系列优化后,持久强度比普通铸造和定向凝固合金显著提高。     

稀土影响高温合金GH907性能的显微机理研究

研究了稀土对GH907合金的力学和物理性能的影响规律,优化了可善GH907合金缺口持久性能,高温抗氧化性能的合金体系,通过比较标准GH907合金和稀土GH907合金的显微组织和界面结构,提出了稀土提高合金性能的微观机理,稀土主要存在于合金的片状相中,使其含量,形态,分布和晶体结构发生改变,与基体之间界面晶格失配和界面应力大小大减小。     

GH220合金热处理制度的探讨

为了探索一种较好的GH220合金热处理制度,使它既具有弯曲状晶界,又具有较高的持久强度和良好的综合性能,我们对该合金进行了十六组热处理方案试验,着重作了等温处理制度、缓冷制度及缓冷加回溶制度的研究。 试验结果表明,晶界强度和晶内强度必须恰当地配合才能获得最佳的     

δ铁素体对ZG1Cr10MoWVNbN耐热钢持久强度的影响

通过对不同淬火温度的ZG1Cr10MoWVNbN耐热钢试样进行高温蠕变持久试验和金相分析,研究了δ铁素体对其持久强度的影响。结果表明:该耐热钢中的δ铁素体呈带状分布,降低了马氏体基体的连续性,使得该钢持久强度下降,并且δ铁素体含量越高,试样持久试验时间则越短;同时由于δ铁素体中固溶了大量合金元素,降低了马氏体基体中的合金元素含量,减弱了马氏体耐热钢的固溶强化和沉淀强化作用,这也会降低该钢的高温持久强度。     

元素V对镍基柱状晶合金显微组织和高温蠕变性能的影响

采用定向凝固炉制备出含有不同V含量的柱状晶合金,进行了高温蠕变性能测试和微观组织形貌观察,研究合金化元素V对镍基柱状晶合金微观组织及高温蠕变性能的影响。结果表明:低V含量的合金中碳化物主要以棒状形式存在,而高V合金中碳化物主要以块状形式存在,棒状碳化物中的V含量低于块状碳化物。随V含量的增加,合金中碳化物由棒状向块状转变,当V含量达到1.04%(质量分数)时,碳化物的形貌已经完全转变成块状。铸态合金经固溶处理后,合金中的碳化物发生溶解,低V合金中的棒状碳化物溶解较多,而高V合金中碳化物溶解较少。在980℃/216 MPa和760℃/725 MPa条件下低V柱状晶合金持久寿命较短,高V合金持久寿命较长,提高合金中的V含量有利于提高合金的蠕变寿命。高V合金与低V合金相比,时效和蠕变期间在晶界析出M_(23)C_6型碳化物数量少。蠕变期间合金中的裂纹主要在晶内MC型碳化物及晶界析出的M_(23)C_6型碳化物处萌生和扩展。     

GH625合金的冷变形及其对力学性能的影响

研究了冷加工变形量对GH625合金板材力学性能的影响。研究表明,随冷加工变形量的增加,GH625合金的拉伸强度增加,但塑性降低。冷加工变形量对待持久寿命和冷热疲劳性能影响显著,20％左右的冷变形量可使合金具有最挂的持久寿命和疲劳性能及良好的综合力学性能。合金冷作硬化效果与合金的回复和再结晶程度及固溶化处理温度有关。     

Hochtemperaturkriechverhalten der schmelzmetallurgisch hergestellten dispersionsverstärkten Kolbenlegierung AlSi12CuNiMg

This paper deals with the creep behaviour of the titanium carbide reinforced AlSi12CuNiMg piston alloy at 350°C and its comparison to the conventional AlSi12Cu4Ni2MgTiZr piston alloy. With only 0,02 vol‐% TiC reinforcement the creep strength and creep rupture strength of the AlSi12CuNiMg piston alloy are significantly improved and reach the level of the expensive AlSi12Cu4Ni2MgTiZr alloy.     

Nb对HP合金组织与蠕变断裂强度的影响

随 Nb 含量的增加,HP 合金蠕变断裂强度的变化表现出极大值特征。在含碳0.4(wt%)的HP 合金中添加0.5(wt%)以下的 Nb,主要起固溶强化作用;当 Nb 量约1.5(wt%)时,可以获得最佳的蠕变断裂强度。其原因是在共晶组织中形成了形态复杂的共晶 NbC,在晶内析出了高度弥散的二次 NbC,以及由于 Nb 的加入提高了组织稳定性;当 Nb 量进一步提高时,由于共晶 NbC 形成了片层状共晶团以及晶内 M_(23)C_6大量减少使蠕变断裂强度下降。     

GH36合金材料高温持久强度断裂时间分布研究

采用数理统计方法，对ＧＨ３６合金材料试验数据进行高温持久强度断裂时间的概率特性分析，研究其分布规律。为进一步可靠性分析和持久强度外推提供理论基础。     

Effects of Rhenium on Creep Rupture Life of a Single Crystal Superalloys

1.Intr0ductionSince1980'stheturbinebladefabrication0fsinglecrystalsuperall0yshasbeenone0fthesignificantkeytechnol0giesofaeroengine.Atpresentsinglecrystalsuperalloysarebeingusedtofabricatethebladesofaeroengineswithpushweightrati01O,suchasaer0-engineFll9(U.S.A.),Fl2O(U.S.A.),GE90(U.S.A.),EJ200(England,Germany,ItalyandSpain),M88-2(France)andP2000(Russia).Thesinglecrystalsuperalloysofthefirstgenerati0n,secondgenerati0nalldthirdgenerationhavebeenstudiedandappliedt0thebladesandvanesofaeroe…     

高Nb-TiAl合金的凝固组织与力学性能研究

研究了Al含量变化对高Nb-TiAl合金的凝固组织与力学性能的影响.结果表明:随着Al含量的增加,TiAl合金晶粒尺寸呈增加趋势;当Al含量为45.7%时,凝固过程中局部区域发生包晶转变,使晶粒尺寸显著增大;室温及700℃高温拉伸强度随着Al含量的增加而呈增加的趋势,但发生包晶转变致使室温及700℃高温拉伸强度下降约200MPa;Al含量对延伸率不敏感,持久性能随Al含量的增加呈增加趋势.为控制铸锭凝固后的组织与力学性能,尽量避开包晶转变区,合金中Al含量应低于45.7%.     

Characterisation of Laves phase precipitation and its correlation to creep rupture strength of ferritic steels

The Laves phase precipitation process was characterised by means of field emission scanning electron microscopy to demonstrate its effect on creep rupture strength of steels with a fully ferritic matrix. To eliminate the effects of carbide and carbonitride precipitations so that the creep rupture data can be analysed exclusively in relation to the Laves phase precipitation process, an alloy Fe–9Cr–3Co–3W (wt.%) without C and N additions was used for the study. Creep rupture strengths were measured and volume fraction and particle size of Laves phase precipitates in the ruptured specimens were analysed. It was found that the creep rupture strength started to collapse (or decrease more rapidly) long before the Laves phase precipitation reached equilibrium fraction. This was related to the onset of the coarsening of Laves phase particles, which precipitated only on grain boundaries and hence contributed little to precipitation strengthening. Creep deformation had no effect either on the precipitation kinetics or on the growth kinetics of Laves phase particles.     

微量镁和锆对GH4133B合金缺口持久及低周疲劳性能影响EI

研究了微量镁和锆对ＧＨ４１３３Ｂ合金涡轮盘高温缺口持久性能及使用性能下的高温低循环疲劳性能的影响。采用光学金相、透射电镜和扫描电镜等进行了显微组织和断口分析。结果表明：镁和锆的微合金化改善了合金的晶界状态，对晶界碳化物起细化、分散和球化作用，使晶内和晶界强度及塑性得到很好的匹配。提高了合金的持久强度和塑性，消除缺口敏感性，同时提高了合金的高温低循环疲劳寿命。     

Der Einfluß von Niob auf die Zeitstandfestigkeit von Schleudergußlegierungen mit 25% Chrom und 20% Nickel

The Influence of Niobium on the Creep Rupture Strength of Centrifugally Cast Alloys Containing 25% Chromium and 20% Nickel . The material most frequently used in chemical furnace construction is G-X 40 CrNiSi 25 20 steel. Because of the change to larger units and the increase in operating pressure and temperature it is often no longer possible to obtain sufficiently long on-stream times with this alloy. The development consequently turned to new alloy variants which held out promise of an improved creep rupture strength, with undiminished resistance to corrosion. By adding niobium to alloys containing 25% chromium and 20% nickel it is possible to improve the thermal stability of centrifugal castings. The creep rupture strength data of two niobium-containing melts of this type of steel were determined experimentally. The creep rupture strength characteristics of the CrNi-containing centrifugally cast alloys with and without niobium was compared by platting the scatter jointly on one chart.     

Microstructural Evolution on the T91 Dissimilar Metal Joints during Creep Rupture Tests

T91 steel is one of the new materials presently employed in power plant pipe components. The creep rupture strength and microstructure of the T91+10CrMo910 and T91+13CrMo44 welded joints were analyzed during creep rupture tests. Creep transgranular ductile rupture occurred at the 10CrMo910 matrix in the T91+10CrMo910 welded joints and creep intergranular brittle rupture occurred at the 13CrMo44 HAZ in the T91+13CrMo44 joints. Microhardness measurements showed high hardness at the heat affected zone (HAZ) of T91 and a sharply drop at the 13CrMo44 HAZ during creep rupture. The metallographic tests showed that no obvious microstructure degradation was observed in the 10CrMo910 HAZ and matrix, while creep cracks appeared at the 13CrMo44 HAZ. T91 steel had relatively high creep resistant strength in the welded joints tested. Recovery occurred in the T91 HAZ with the growth of subgrain size and the decrease of dislocation density during creep. It was concluded that the dissimilar joints of T91 and low alloy h