Research on influence of typical microstructure characteristics of Ni base single crystal on creep rupture and deformation analysis of turbo blade

Considering the influence of typical microstructure characteristics on creep performance,a series of UM-F single crystal alloys which had similar element components but different microstructures were used to analyze the relationship between creep life and microstructure characteristics of Ni base single crystal.Three main factors were proposed:misfit,volume fraction of precipitate and maximum matrix channel width.The Microstate parameter Ymicro was established to estimate the deformation state of the materials.The linear relationship between the initial value of microstate parameter Y0 and creep life under a certain temperature/load was affirmed.By analyzing the high temperature region of turbo blade using the material parameters of DD 3,the creep deformation and the life prediction of the critical points of blade were obtained and the result closed to the test.     

Yield anisotropy and tension/compression asymmetry of a Ni3Al based intermetallic alloy

In order to investigate the yielding behavior of the newly developed Ni 3 Al-based intermetallic alloy IC10, yield stresses have been measured in tension and compression with different orientations. The specimens were cut from a sheet with different angles inclined from the solidification direction. The inclined angles were taken to be 0 , 22.5 , 45 , 67.5 and 90 . All experiments were conducted at room temperature except for orientation 0 , whose deformation temperatures ranged from 298 to 1273 K. Experimental results show that the yield strength of alloy IC10 has the anomalous behavior which has been observed for other Ll 2 -long-range ordered intermetallic alloys, but it is less pronounced. The abnormalities show the following characteristics: (i) the yield strength increases as the temperature is raised below the peak temperature, (ii) yield strength anisotropy, (iii) tension/compression asymmetry. Compared to Ni 3 Al single crystals, the polycrystalline exhibits some different yielding behaviors which may be due to the high volume fraction of c phase.     

Invar36合金端面铣削力研究

为了研究Invar36端铣过程中切削参数对切削力的影响规律,进行了切削力的单因素实验。对比分析了Invar36与0Cr18Ni9的切削力,研究了切削过程中切削力信号的产生及特征,并对加工过程中的动态切削力进行了频谱分析。分析了切削速度、每齿进给量和轴向切深对切削力的影响规律,建立了切削参数与切削力之间的数学模型。结果表明:刀具坐标系内的径向分力Fr表征了工件对刀具后刀面的挤压作用,单个切削周期内的切向铣削力Ft的峰值超前径向铣削力Fr的峰值。回归模型中的相关系数表明,切削参数对切削力影响的显著性依次为轴向切深、每齿进给量、切削速度。随着轴向切削力的增大,试件表层的Invar36晶粒扭曲程度更加明显,晶粒扭曲深度也随之加深。     

TiNiFeNb形状记忆合金的组织结构及相变特性

通过向TisoNiso合金中加入Fe和Nb元素,制备出一种四元Ti49Ni50-xFexNb1形状记忆合金.采用X射线衍射和背散射电子衍射的方法,测试和分析了合金的相结构及微观组织形态,采用电阻法系统研究了合金的相变特性.结果表明:Nb元素的加入并没有改变TiNiFe合金的B2结构,仅导致了广极少量的富Nb相在基体中析...     

Ni含量及超声振动对激光熔覆中裂纹的影响

增加熔覆粉末中N i含量可以减少熔覆层中的硬质相,使熔覆层脆性降低,韧性提高,因而提高熔覆层在冷却过程中对拉应力的承受能力,减少熔覆层裂纹;而在熔覆过程中施加超声振动,则可以打碎枝晶,细化晶粒,减少或消除拉应力产生的根源,并使熔池化学成分、温度分布趋于均匀,从而减少裂纹的产生几率。     

含Ni夹层SiCp/2014Al铝基复合材料扩散焊

利用中间添加Ni层,在610℃保温60min工艺成功实现了SiCp/2014Al铝基复合材料的真空扩散焊接.焊接之后利用金相显微镜(OP)、扫描电镜(SEM)、电子探针(EPMA)等对焊接接头进行分析.分析表明,Ni和Al之间相互扩散形成由金属间化合物构成的中间过渡层,主要由Ni3Al//NiAl//NiAl3组成.在理论上,计算出Ni和Al元素扩散浓度与焊接温度和保温时间之间的关系,以及元素的扩散距离与焊接参数之间的关系呈抛物线形变化.     

A Novel Processing Route for Ni-doped Alumina Composites

Alumina-based composites containing 0-15wt% Ni metallic phase were produced by hot press-sintering Ni-coated alumina pow-ders. The Ni-coated alumina powders were prepared by the aqueous heterogeneous precipitation of alumina micro-powders and nickel sulfate salt followed by reduction process. The microstructural features and dispersion of Ni phase in Ni-coated alumina powders and the subsequent alumina-Ni cermets were investigated using scanning electron microscope (SEM), X-ray diffractometer (XRD), and trans-mission electron microscope (TEM). The relative density of the hot press-sintered composites was measured with the Archimedes’ method while the fracture strength and the fracture toughness were defined with the three-point bending method and the mi-cro-indentation fracture method. In the formation of alumina-Ni cermets from sintered Ni-coated alumina powders, Ni phase to some extent limits the densification rate and stifles the coarsening and growing process of alumina grains. The Ni phase is found to be located at the interfaces and the triple-joint junctions of alumina grains which results into alteration of the fracture mode of alumina and its in-creased fracture strength and fracture toughness if compared with monolithic alumina.     

2Cr16Ni2MoN不锈钢组织与性能研究

通过拉伸测试、冲击测试、硬度测试、透射电镜及扫描电镜观察分析等手段研究了不同热处理状态下2Cr16Ni2MoN不锈钢的组织与性能.研究结果表明,钢采用低于1000℃的固溶温度,组织中存在未溶的(Cr,Mo)23C6,当固溶温度高于1100℃时,马氏体板条明显粗化,均对钢的力学性能不利,钢比较适宜的固溶温度为1040℃.该钢时效硬化的主要原因是组织中析出与基体共格的(Cr,Fe,Mo)2C碳化物.钢经1040℃固溶,560℃时效可以获得较好的强度与韧性配合.     

航空用不锈钢焊接导管的损伤容限研究

基于断裂力学方法开展了1Cr18Ni9Ti导管TIG焊对接结构的损伤容限分析,在测试其母材和TIG焊接头拉伸性能、断裂韧度和疲劳裂纹扩展速率的基础上,分析其失效模式,确定损伤容限ac。研究结果表明:1Cr18Ni9Ti导管TIG焊对接结构在工况振动载荷下,损伤容限ac为0.9mm,导管失效形式为泄露。     

枪黑色Ni/Sn合金在NaOH溶液中的析氢电催化性能

实验测出的电化学参数表明：在ＮａＯＨ溶液中电解制氢时,枪黑色Ｎｉ／Ｓｎ合金的析氢电催化性能比４５号钢和主硫镍的强很多,而且具有很主的电化学稳定性。