简介:ScanningElectronMicroscopyStudiesofYBa_2Cu_3O_(7-δ)SuperconductorsShaWei(沙维)(DepartmentofCivilEngineering,TheQueen′sUniversit...
简介:根据PCB市场发展趋势以及汽车终端需求,汽车电子在未来5到10年会保持长期稳定增长,预计每年增幅约为10~15%。很多大型PCB厂都对汽车电子表示了极大的兴趣。覆铜板行业的企业纷纷投入布局汽车基材产品。但是,汽车电子基板对产品性能可靠性和稳定性、供货环节等要求甚高,基材生产商在研发、生产、供应、管理环节必须非常强大。广东生益科技有限公司是中国覆铜板
简介:灼伤抵抗的钛合金的开发是在喷气引擎减轻钛火的点火和繁殖的最直接的方法。WSTi3515S合金(Ti-35V-15Cr-0.3Si-0.1C)是一种新高alloying贝它类型灼伤抵抗的钛合金,属于在在过去设计技术被使进步重要的Ti-V-Cr类型合金5?年。象有弹性的性质那样的WSTi3515S灼伤抵抗的钛合金的物理性质和热性质处于不同条件被测量并且分析。结果两个都显示出那幼仔模量并且砍WSTi3515S合金减少的模量稍微变化,温度在测试温度增加。WSTi3515S合金的泊松比率在0.36附近。然而,象特定的热,热扩散性,热传导性和热扩大那样的热性质增加,温度增加,它源于在提高的温度加强格子热颤动。并且WSTi3515S合金的房间温度密度是5.295?g????????????敮睴牯晫牯??
简介:Thequenchsensitivityandtheirinfluentialfactorsof7,021,7,085,and7,050alloyswereinvestigatedbytheendquenchingtestmethodandthemeasurementofelectricalconductivity,hardness,andmicrostructureafteraging.Theresultsindicatethat7,050alloyhasthelargestchangeswithhardnessdecreasingfromHV199toHV167,andelectricalconductivityincreasesfrom16.6to18.2MSm-1whenthedistancefromquenchedendincreasesfrom2to100mm.Alloys7,085and7,021haverelativelysmallerchanges.Accordingtotherelationshipbetweenthehardnessandelectricalconductivityofasupersaturatedsolidsolution,7,050alloyhashigherquenchsensitivitythan7,085and7,021alloys.Themicrostructureof7,050alloywithhighermajoralloyelement(Zn+Mg+Cu)additionandCuelementadditionismostlyaffectedbythechangesofdistancefromquenchedend.In7,050alloy,thesizeofintragranularprecipitatesisfromabout10–200nm,andthe(sub)grainboundaryprecipitatesareabout20–300nm.Alloy7,085withlowerCucontentismoderatelyaffected,while7,021isleastaffected.Itisfoundthatwiththeincreaseofdistancefromquenchedend,quenched-inducedprecipitatepreferentiallynucleatesandgrowsinthe(sub)grainboundaryandthenonthepre-existingAl3Zrparticles.