SiCp／Al复合材料高应变率压缩变形及损伤机理

采用真空热压工艺制备了含SiC颗粒体积分数分别为5%,15%和25%的SiC颗粒增强铝基复合材料,利用Hopkinson高速压杆冲击实验系统对其从静态到动态(应变率为3.3×10-3s-1～5.2×103s-1)的压缩破坏响应进行了研究,结合其光学显微镜分析变形组织,分析了不同体积分数SiCp/Al复合材料高应变率压缩载荷下,材料的变形和微观损伤机理.结果表明,复合材料存在应变率敏感性,SiC含量的增加导致复合材料应变率敏感性的增加,以垂直于载荷方向的增强相颗粒的剪切开裂为主要破坏模式.     

Mn含量对0.15C-0.6Si-Mn TRIP钢组织和力学性能的影响

经过在两相区退火和贝氏体区等温处理，研究了两种不同锰含量的低硅TRIP钢的组织和力学性能，试验结果表明，低硅和低锰钢的残留奥氏体量少，力学性能差；增加锰含量，能提高残留奥氏体量及拉伸强度和伸长率，其力学性能与常规低碳Si-MnTRIP钢的水平相关，用电子探针测试了两相区退火钢中锰和硅的分布情况，发现锰在临界区退火时不发生再分配。     

EFFECTS OF SPECIFIED BLANK SIZE ON BODY WRINKLING DURING HYDRODYNAMIC DEEP DRAWING OF TAPERED RECTANGULAR BOX

1.~nonHydridapawhcdeepdrawing(HDD)belongstothefieldofsheetmetalfoeingandcanbeaPPliedinthefieldofautomotive,aerospace,drilitaryindustryetc.Ithasbeenrecognizedwidelyintheworld["'j.Fig.Ishowsitsprinciple:TheliqUidthatisfilledinthe~ngdiecavitywillbepressedwhenthepunchgoesdownsothattheeffectoffrictionkeepingandoverflowlubricatingcanbeformed,astherestilt,thefoeinglicitofsheetmetalwillbeimprovedareailvandthegualitVofthefinishedpartswillbeup~ed.BecauseofmanyadvantagesofHDDprocees,ithasbeenwidelys…     

WX-Ⅰ型酸洗缓抑剂的应用试验

介绍了 WX—Ⅰ型缓抑剂的缓蚀抑酸雾机理,通过降低酸耗及金属损耗的使用试验结果表明,采用该缓抑剂可使钢管成材率提高o.5%,年直接经济效益达到5.2万元,并且大大减少环境污染。     

A study of the corrosion properties of plasma nitrocarburized and oxidized AISI 1020 steels

Plasma nitrocarburized AISI 1020 steels were oxidized for 15, 30 and 60 min to evaluate their corrosion and microstructural properties. After plasma nitrocarburizing for 3 h at 570°C in a gas mixture comprising 85 vol.% N₂, 12vol.% H₂ and 3 vol.% CH₄, the compound layer composed of ɛ-Fe_2–3(N,C) and γ’-Fe₄(N,C) phases and the diffusion layer above the matrix were observed. The top oxide layer, consisting mainly of magnetite (Fe₂O₄) and hematite (Fe₂O₃) phases, forms after post-oxidation treatment at 500°C. However, the oxide layer was severely degraded by spallation as a result of increases in post-oxidizing time. The difference in corrosion resistance should be attributed to the thickness of the top oxide layer, which was governed by post-oxidizing time.     

消除铸件内应力应注意的几个问题

在对湖南、江西等厂调研的基础上,结合笔者多年的经验,提出了灰铸铁生产中,消除铸件内应力时应注意的几个问题.生产中只有严格控制加热速度、加热温度、保温时间以及冷却速度,才能有效地消除铸件内应力,保证产品质量.     

基于CAN总线DZY300型运梁车转向系统设计与工程实现

本文介绍了上海磁悬浮工程专用DZY300型运梁车的转向系统设计原理与实现过程。以CAN总线为基础，来实现转角信号的实时检测和电液比例阀的远端控制；从而利用总线通讯技术，实现了大闭环控制系统。在采用经典PID控制律时，针对工程实际情况进行了改进。理论充分与实际相结合，保证调节实时性的同时，有效地解决了转向系统中出现的超调振荡、反复微调节和调节不平稳现象。     

The improvement of thermal error modeling and compensation on machine tools by CMAC neural network

In this paper, a cerebellar model articulation controller (CMAC) neural network is proposed for thermal error modeling in machine tools. The CMAC is a systematic learning algorithm which can search for the nonlinear and interaction characteristics between the thermal errors and temperature field on the machine tools. The CMAC is investigated in terms of accuracy in prediction, robustness to sensor placement, speed of learning, and tolerance to sensor failures. Experimental measurements of the spindle drift errors for both a horizontal machining center and a CNC turning center were performed using capacitance sensors and thermal sensors. Results show that the CMAC model has better performance than other modeling methods in robustness to sensor placement and speed of learning. This makes determination of the sensor locations easier, and reduces calibration time. In addition, a sensor failure detection algorithm is developed to provide better reliability.     

搅拌摩擦加工(FSP)AZ91D镁合金的组织分析

研究了AZ91D镁合金经搅拌摩擦加工后的组织。发现组织中搅拌摩擦区、热机械影响区和热影响区分区不明显。在搅拌摩擦区主要为再结晶形成的细小均匀的等轴晶结构,共晶组织α-Mg β相(Mg17Al12)完全均匀化,仅在晶界处有少量存在。     

盐浴硫氮碳共渗45钢的接触疲劳性能

对４５钢经盐浴硫氮碳共渗处理的大批试样，进行了滚子接触疲劳性能试验，绘出了Ｐ－Ｓ－Ｎ曲线，分析了接触疲劳断口形貌及破坏机理。