微量Y对Al—Li合金的析出相和力学性能的影响

研究了Y(0.1、0.5wt-％)对Al-Li-Cu—Mg—Zr合金析出相与拉伸性能的影响结果表明:Y可使铸态合金晶粒细化:促进β′(Al_3Zr)相析出:抑制δ′(Al_3Li)相的长大速度:使S′(Al_2CuMg)相的分布均匀化.添加0.1％Y能改善合金塑性而不降低强度:添加0.5％Y可使强度提高而塑性不降低     

BEHAVIOUR AND MECHANISM OF STRESS CORROSION CRACKING FOR Al-Li-Cu-Mg ALLOY

Studies were made of the influence of aging conditions and applied potentials on thestress corrosion carcking(SCC)susceptibility for an Al-Li-Cu-Mg alloy by slow strainrate technique.The relationship between the relative hydrogen content on specimensurface,the applied potentials and elapsed time has also been examined.The SCCsusceptibility was found to be dependent on aging conditions in which the peak agedcondition gave the worst SCC resistance and the natural aged condition had the best one.The SCC susceptibility and surface hydrogen content relates to the applied potentials.The anodic potentials increase SCC susceptibility,while the cathodic ones below thecritical potential accelerate SCC.It is considered that both the anodic dissolution and     

MICROSTRUCTURE OF MARTENSITE IN Cu-14Al-4Ni ALLOY AGED FOR A PROLONGED TIME AT ROOM TEMPERATURE

The microstrueture in shape memory alloy Cu—14Al—4Ni aged for two years at room temper-ature has been studied,and the substructure slow change has been observed.The domains ofhighly ordered phase and the transition regions appear at grain boundaries,the twin bounda-ries damage.Furthermore,the microstructure also gives the appearance and growth ofantiphase domains like rectangular network.The long period antiphuse boundary structuresand the antiphase domains have bee.observed first at the single diffracted vector .The con-centration gradient of solute atom Al has heen found from the matrixes to the grain bounda-ries,the matrixe is poor in Al and the grain boundaries are rich in Al.     

自蔓延高温合成钴-钛系多孔合金

采用自蔓延高温合成制备了Co-Ti多孔体新型人体骨、关节材料。以Ti粉和Co粉按原子比Ti∶Co=1∶1与Ti∶Co=2∶12种配比的原料,在10Pa负压条件下,500℃预热2min点燃进行自蔓延合成反应。对反应产物进行XRD分析和SEM观察及力学性能测试。结果表明,2种合成产物分别为单相CoTi和CoTi2。CoTi的结构和力学性能比CoTi2优越。其孔隙率为40.9%,抗压强度308MPa,抗折强度134MPa,弹性模量11.6GPa,与人体骨、关节具有很好的力学性能相容性。因此用SHS法制备的CoTi多孔合金有望作为一种新型人体植入材料获得开发应用。     

电磁连铸过程中电磁场对变形镁合金凝固组织的影响

采用软接触电磁连铸和普通连铸的方法分别制备了AZ61镁合金铸锭,结果表明软接触电磁连铸铸锭的组织均匀,晶粒细化,晶界上二次相析出减少,第二相呈断续状弥散分布,Al元素含量在晶内增加,而在晶界处降低。针对上述现象探讨了连铸过程中电磁场作用下AZ61镁合金的组织凝固机理,提出第二相"磁致弥散"的思想,并推导了软接触电磁连铸的热力学关系。     

钛合金髋关节铸造工艺CAD及模拟验证

设计了钛舍金髋关节的金属型离心铸造工艺方案，并对其充型过程和凝固过程进行了数值模拟验证，得到了较合理的铸造工艺方案，实际浇注表明，工艺是合理的。首先针对钛舍金髋关节的结构特点进行了分体模数计算，在此基础上，根据钛舍金的铸造工艺特点进行了铸造工艺设计，即将钛舍金髋关节分5个部分进行补缩，浇注速度要大，浇注时间要短，真空度要高，浇注温度大于等于1760℃。进行工艺优化后，数值模拟结果和实际浇注表明，设计可以满足要求。     

Preparation and properties of alloy 2618 reinforced by submicron AIN particles

An attempt was made to explore the possibility of fabricating AA2618 reinforced by submicron AIN particles. The results show that the addition of AIN particles decreases remarkably the grain size of the alloy. The 2618-AIN dispersion-strengthened alloy has the same strength as AA2618 at room temperature in the T6 state, but exhibits significantly higher strength after isothermal exposure at 200 °C for 100 h. The strength of the dispersion-strengthened alloy at elevated temperatures was greater than that of AA2618.     

热变形高铌Ti-Al合金获取全片层组织的热处理工艺

研究了热变形高铌Ti-Al合金获取全片层组织的热处理工艺及转变机理,提出了新的热处理工艺为:1480℃×10min→1345℃×20min→900℃×2h,空冷。采用新工艺热处理时可使高铌Ti-Al合金中在β相与α相区两次重新形核长大,破坏了原始变形组织中晶粒间的取向关系,从而得到了均匀的α相,因而新工艺热处理后得到较为均匀细小的全片层组织。     

Ni-Cr-Fe-Si-B合金涂层及铝青铜基体熔合区组织的研究

采用钨极氩弧焊方法在铝青铜基体上施焊了Ni—Cr-Fe-Si—B合金涂层，并运用金相显微镜、扫描电子显微镜及能谱分析了喷涂层、熔合区及热影响区的组织形貌和成分分布。结果表明，喷焊时，在涂层与基体界面两侧各组元均发生了明显的扩散，Cu、Ni组元间可相互取代，基体融合区组织的基本组成仍为α (α γ2)，但同时也形成了Cu2FeAl7、NiAl3等新相，且融合区组织细小，涂层与基体间为冶金态结合。     

Microstructures of worn surface and wear debris of as-cast Al-17Si-xLa alloys under unlubricated conditions

1　INTRODUCTIONAl Sialloyshavebeenwidelyusedasthetribo logicalcomponentsininternalcombustionenginesfortheirhighresistancetowearandseizure ,andhighspecificstrength .Therefore ,thewearbehaviorsofAl Sialloysagainstvariouscounterfaces (typicallyacastironcounterface)havebeeninvestigatedexten sively[16 ] .Themutualtransferofmaterialbetweentwoslidingcounterfacesisinvariablyinvolvedinawearprocess ,especiallyunderdryorunlubricatedconditions ,leadingtotheformationofamechanicallymixedlayerattheworn…