Y.T. Xi
,
D.X. Liu
,
D. Han
,
Z.F. Han
,
null
,
null
,
null
,
null
金属学报(英文版)
A series of experiments were carried out to study the influence of low temperature plasma nitriding on the mechanical properties of AISI 420 martensitic stainless steel. Plasma nitriding experiments were carried out for 15 hours at 350℃ by means of DC-pulsed plasma with 25%N2+75%H2 gas. The microstructure, phase composition and residual stresses profiles of the nitriding layers were determined by optical microscopy and X-ray diffraction. The microhardness profiles of the nitriding surfaces were also studied. The fatigue life, sliding wear and erosion wear loss of the untreated specimens and plasma nitriding specimens were determined on the basis of a rotating bending fatigue tester, a ball-disk wear tester and a solid particle erosion tester. The results show that the 350℃ nitriding surface is dominated by -Fe3N and , which is supersaturated nitrogen solid solution. They have high hardness and chemical stabilities. So the low temperature plasma nitriding not only increases the surface hardness values but also improves the wear and erosion resistance. In addition, The fatigue limit of AISI 420 steel can also be improved by plasma nitriding at 350℃， because plasma nitriding produces residual compressive stress inside the modified layer.
关键词:
Martensitic stainless steel
,
stainless
,
steel
,
Plasma
,
nitri
Li XING
,
Jie ZHAO
,
Fuzhong SHEN
,
Wei FENG
材料科学技术（英文）
A Z-parameter method is used to evaluate the damage process of HK40 austenitic steel. By using Z-parameter based on the Larson-Miller method, the nonlinear master curve of the log stress vs Larson-Miller parameter P can be expressed as: P=27.74-3.4lgσ-0.032σ, and a family of curves parallel to the master curve can be written as: P=(27.74-Z)-3.4lgσ-0.032σ, where Z represents the magnitude of the deviation from the master curve. According to the creep rupture data both from different segments of a serviced tube and from the same segment locations with different service time, the value of parameter Z has close relationship with the deterioration of creep rupture properties. The damage state of the samples is evaluated by monitoring the changes in natural frequency f and Young0s modulus E, and the relationships between Z and the damage parameters are discussed.
关键词:
Damage evaluation
,
蠕变断裂
,
奥氏体钢
,
Z参数
王晓旭
,
陈利
材料工程
doi:10.3969/j.issn.1001-4381.2011.11.001
通过单根Z-pin从复合材料层合板中拔出的试验方法,测试了Z-pin的拔出强度,计算了Z-pin的临界埋入深度,并引入抗拉强度利用率概念来表征Z-pin的抗拉强度在拔出过程中的利用程度.结果表明,直径0.50mm和0.28mm的Z-pin临界埋入深度分别约为5.1mm和3.1mm.当Z-pin的埋入深度小于临界埋入深度时,Z-pin从层板中拔出；Z-pin拔出强度与埋入深度成正比,与Z-pin的直径成反比；当Z-pin的埋入深度大于临界埋入深度时,Z-pin发生断裂,Z-pin的抗拉强度利用率达到100％.最后提出了提高抗拉强度利用率的建议.
关键词:
Z-pin
,
拔出强度
,
复合材料
,
拔出试验
,
抗拉强度
王晓旭
,
陈利
航空材料学报
doi:10.3969/j.issn.1005-5053.2011.4.017
通过三种复合材料Z-pin的轴向压缩试验,观察了各Z-pin的压缩行为,分析了三种复合材料Z-pin在不同长度时的极限应力及其失效形式.结果表明,直径为0.50mm的碳纤维Z-pin的压缩性能最好,其各长度Z-pin所能承担的极限应力都较大.直径0.28mm的碳纤维Z-pin易发生失稳现象,芳纶纤维Z-pin在压缩力的作用下,接触端容易受到破坏.两种碳纤维Z-pin临界应力的理论值与试验值吻合较好,但芳纶纤维Z-pin的临界应力的试验值比理论值偏低.
关键词:
Z-pin
,
复合材料
,
压缩试验
,
临界应力
狄国标
,
刘振宇
,
麻庆申
,
刘相华
,
王国栋
钢铁研究学报
在4 300mm宽厚板轧机上进行了自升式平台用厚板F460的工业试验,并对低温韧性和Z向性能进行了研究.结果表明,心部条带状M/A岛导致低温韧性偏低,MnS夹杂物诱发厚度方向(Z向)拉伸断面收缩率不合格.采用降低碳、锰含量并提高轧后冷却速率的方法,避免了条带状M/A岛组织,低温韧性明显改善;通过增加Si-Ca线长度,增强对MnS夹杂物的球化效果,生成细小难变形的复合夹杂物,有利于提高平台用厚板的抗层状撕裂性能.
关键词:
M/A岛
,
低温冲击
,
自升式平台用钢
,
层状撕裂
詹勇军
,
王锋
,
白黎
,
张素银
,
唐永健
,
吴卫东
,
谌家军
材料导报
以材料非线性光学性质的测试为基础,介绍了原始Z扫描技术的基本原理与数据处理;重点论述了双色时间分辨Z扫描技术的理论,并分析了它在材料光学非线性效应测试中展现的优越性以及应该注意的关键问题.根据Z扫描技术理论和实验的最新研究成果,总结了Z扫描技术的两条发展思路,即:CCD相机代替能量或功率计进行信号的采集和多种改进方法应用于实验测试.
关键词:
Z扫描技术
,
非线性光学效应
,
双色时间分辨Z扫描技术
,
CCD相机
