S.S. Xie
,
X.F. Pan
,
T.L. Wang
,
Z.X. Wang
,
H.C. Yang and Q. Wang ( School of Materials and Metallurgy
,
Northeastern Universityl Shenyang 110006
,
China)( School of Materials and Metallurgy
,
Northeastern Universityl Shenyang 110006
,
China)( School of Materials and Metallurgy
,
Northeastern Universityl Shenyang 110006
,
China)( School of Materials and Metallurgy
,
Northeastern Universityl Shenyang 110006
,
China)( Institute of Metal Research
,
The Chinese Academy of Science
,
Shenyang 110015
,
China)( Liaoning Machinery Industry Foreign Trade Co. Ltd.
,
Shenyang 110002
,
China)
金属学报(英文版)
Threshold stress values, muging from ～8 to 16MPa·m1/2 can be obtained in a Ni-base alloy GH586 by varying the microstructure through heat treatments. The threshold and low crack growth rate behaviors at room temperature, with varying groin size and γ'-distribution, have been investigated. The results indicate that grain size is an important microstructurol parameter that affects fatigue crack growth threshold and propagation behaviors, as the values of △Kth increase with increasing grain size, but the γ' -distribution also has important effect. Analyses show that the effects of groin size on threshold and low crack-growth rate behavior result from heterogeneous deformation and roughness-induced crack closure due to crystallographic slipping and cracking in coarse microstructure. The higher △Kth and lower fatigue crack growth rate with increasing amounts of fine γ' phases are closely related to less damage accumulation level in deformation zone of crack-tip resulted from heterogeneous deformation due to dislocations' shearing γ' precipitates.
关键词:
superalloy GH586; fatigue crack growth; threshold; grain size;γ'-distribution
余历军
,
雷闫盈
,
陈立宇
机械工程材料
doi:10.3969/j.issn.1000-3738.2007.12.005
采用四点弯曲试样在高频疲劳试验机上对铝基复合层板进行了疲劳试验,采用直流电势法测量裂纹长度,用扫描电镜和光学显微镜观察其疲劳断口及疲劳裂纹形貌,通过对比性试验,考察了组元性能错配和界面结合强度对复合板L-T取向疲劳裂纹扩展行为的影响,并用断裂力学理论对其进行了初步分析.结果表明:性能错配的复合双层板两侧面的疲劳裂纹扩展通过界面产生牵扯作用,扩展速率相对于整体材料发生变化,近似符合混和定则;界面对层合板L-T取向疲劳性能的韧化作用以分层韧化为主,结合强度不同,产生的影响也不一样.
关键词:
复合层板
,
疲劳裂纹
,
界面结合强度
,
性能错配
尹绍江
,
辛凤英
,
齐长发
,
陈礼斌
金属世界
doi:10.3969/j.issn.1000-6826.2006.04.018
本文结合唐钢FTSR生产线的实际生产工艺参数,利用Gleeble 3500C热模拟机,分别研究了单道次不同变形温度、变形速率(50%压下率)对高强低合金T510L钢变形抗力和奥氏体微观组织演变的影响及两道次(R1→R2)连续变形后奥氏体微观组织演变.实验表明通过高温大压下量的变形,完全可使该钢种充分发生动态再结晶,细化奥氏体晶粒度.
关键词:
FTSR
,
变形温度
,
变形速率
,
动态再结晶
周元鑫
,
夏源明
材料科学与工艺
doi:10.3969/j.issn.1005-0299.2001.04.001
利用MTS810试验机和自行研制的冲击拉伸试验装置对T300/Al复合丝实施了不同应变率下的拉伸试验,获得了材料从0.001 s-1到1 300 s-1应变率范围内完整的应力应变曲线.结果表明:T300/Al是一种应变率敏感复合材料,随着应变率的提高,材料的拉伸强度、失稳应变均相应提高,具有明显的应变率强化效应和动态韧性现象,这主要是由铝基体的应变率强化效应和应变率历史效应引起的.根据材料在不同应变率下的试验结果以及对其不同变形阶段机理的分析,提出了弹塑性复合丝束模型,并由此建立了相应的应变率相关的一维统计损伤本构方程,模型拟合结果与试验结果一致.
关键词:
T300/A1复合丝
,
应变率效应
,
统计模型
Journal of Materials Research
The morphology of the dark and bright regions observed by transmission electron microscopy for the Zr(64.13)Cu(15.75)Ni(10.12)Al(10) bulk metallic glass strongly depends on the ion beam parameters used for ion milling. This indicates that the ion beam could introduce surface fluctuation to metallic glasses during ion milling.
关键词:
room-temperature
焦成革
,
候淑娥
,
李春玉
,
张禄山
材料研究学报
研究了7075T73510合金的断裂韧性和疲劳裂纹扩展行为,分析了不同方向性能差异的原因结果表明:合金的断裂韧性依赖于取向,L—T方向的断裂韧性值远大于T—L方向,而其疲劳裂纹扩展速率对应力比更敏感,无论T—L还是L—T方向,R=0.6时的FCGR值是R=0.1时的二倍左右.在相同应力比和较小的△K下,两个方向的FCGR值基本无差异文中认为:呈带状分布或串状分布的杂质相对T—L向断裂韧性影响较大
关键词:
7075合金
,
null
,
null
H. Y. Zhao
,
A. L. Lu
,
Q. Y. Shi and F. Yan (Welding Division
,
Department of Mechanical Engineering
,
Tsinghua University
,
Beijing 100084
,
China)
金属学报(英文版)
T-joints are widely used in ship manufacturing and other welding structures.The welding residual stress and deformation hare significant influence on failure and service life in welding structures.By us- ing of 3D thermal elasto - plastic FEM, the temperature fields,stress fields and deformation of weld- ing processes on T - joints are analyzed in this paper.The moving heat source is considered in the com- putation. Moreover, weld metal filling and multiple - pass welding are simulated using activate/deac- tivate ability.For avoiding "locking" in full integration elements of welding computation,the re- duced intergration elements are used in weld area.The nonlinear FEM analysis program MARC is used to complete the computations, as well as its user subroutines that are programmed to develop the special techniques needed in the simulation of welding process.Some different welding procedures are com- pared, and the welding residual stress and deformation are discussed in details.
关键词:
welding
,
null
,
null
,
null
,
null
吴珞菲
,
成强
,
李铸国
材料工程
doi:10.11868/j.issn.1001-4381.2015.000051
基于某汽车公司提出的曲面焊接设计需求,研究了变形对焊接组织的影响.选用熔化极气体保护焊在奥氏体不锈钢304L的T型接头和变形钢板上焊接,寻求合理的变形后焊接参数并观察变形对焊接组织的影响.得到合理焊接参数为焊枪速率4mm/s,送丝速率2.5m/min,电压17V.在T型和变形后焊接中,焊趾分别处于应变为0％,30％的区域,观察到变形后焊接件中熔化区和部分熔化区范围减小,焊接接头碳化物沉积和晶间铁素体数量减小.304L变形后焊接获得了更为均匀的接头组织.
关键词:
预变形
,
熔化极气体保护焊
,
焊接工艺
,
微观组织
Chinese Physics Letters
The magnetic properties of 1 T-TaS2 and 1 T-Fe-0.07 Ta-0.93 S-2 have been studied, Experimental results show that the phase transition temperature of 1 T-TaS2 is a function of the magnetic field, At low temperatures, both compounds are in a mixed state of charge density wave -spin density wave due to the coherent superposition of antiferromagnetic coupling.
关键词:
density
