INVESTIGATION OF TENSILE STRESS GENERATED BY PASSIVE FILM DURING CORROSION PROCESS FOR α-Ti

本文研究α—Ti在腐蚀过程中钝化膜所产生的内应力的大小。结果表明,一边涂有保护层的α－Ti薄条在0.1mol／LH2SO4溶液中自然腐蚀过程中,随着钝化膜的形成,薄条不断向腐蚀面弯曲（保护面鼓起）,即在试样表层产生一个拉应力。这个附加拉应力不断增大,其最大值为（5个试样平均）,接近或等于屈服应力。在SCC过程中这个附加应力将和外应力叠加,促进位错发射和运动,从而在低应力（或低KI）下导致SCC裂纹形核。     

IN SITU TEM STUDY OF DISLOCATION EMISSION AND MICROCRACK NUCLEATION FOR α-Ti AFTER ADSORBING Hg

用自制的恒位移加载台,在ＴＥＭ中原位观察了α－Ｔｉ在Ｈｇ蒸汽中放置前后加载裂纹前端位错组态的变化以及脆性微裂纹的形核和扩展。并和α－Ｔｉ在ＴＥＭ中原位伸的结果进行了比较。结果表明：加载裂纹吸附Ｈｇ原子后能促进位错的发射,增殖和运动;当吸附促进位错发射和运动达到临界状态时,脆性微裂纹就在原裂纹顶端或在无位错区中形核并解理扩展。     

PLASTIC DEFORMATION REGULARITY OF TAILOR-WELDED TUBE (TWT) WITH DISSIMILAR THICKNESS DURING HYDRO-BULGING

为揭示差厚拼焊管内高压胀形的变形规律, 采用有限元数值模拟和实验并结合力学分析, 研究了差厚拼焊管胀形时薄壁管、厚壁管的变形差异, 及塑性区的发生、发展过程和促进变形协调的力学和几何因素, 分析了差厚变形条件下薄壁管、厚壁管的应力、应变发展历史. 结果表明: 差厚拼焊管内高压胀形时, 厚壁管的变形始终落后于薄壁管. 薄壁管中部最先屈服, 塑性区自中部向两端逐渐扩展, 厚壁管靠近焊缝端先屈服, 随着内压升高塑性区逐渐扩展到另一端. 变形强化和长度比增大可促进两管协调变形. 无论长度比如何变化, 整个变形过程中薄壁管轴向应变始终为拉应变, 厚壁管轴向始终为压应变.     

MAGNETIC PROPERLIES AND STRUCTURE OF A MIXTURE OF α-Fe and Fe_3N DURING MECHANICAL ALLOYING PROCESS

利用X射线衍射研究了α-Fe与Fe3混合粉末机械合金化过程中结构的变化．并测量了球磨不同时间后其饱和磁化强度的变化结果表明,随着球磨时间的延长,Fe3N相迅速分解直至消失,N原子部分固溶于α-Fe中,24h后可形成稳定的α-Fe（N）过饱和固溶体,其中N的质量分数约为0．290％-0．346％．随着球磨时间的延长,α-Fe的晶粒尺寸逐渐减小,24h后趋于定值,约为8nm．球磨引起样品中Fe原子周围N原子位置的变化,使得球磨过程中混合粉末的饱和磁化强度开始时降低,5h后又有所增加,24h后达到一定值     

MATHEMATICAL MODEL AND COMPUTER SIMULATION OF MOISTURE TRANSFER PROCESS DURING SINTERING

ＭＡＴＨＥＭＡＴＩＣＡＬＭＯＤＥＬＡＮＤＣＯＭＰＵＴＥＲＳＩＭＵＬＡＴＩＯＮＯＦ　ＭＯＩＳＴＵＲＥＴＲＡＮＳＦＥＲＰＲＯＣＥＳＳＤＵＲＩＮＧＳＩＮＴＥＲＩＮＧＺｏｕ；ＺｈｉｙｉＨｕａｎｇ；ＴｉａｎｚｈｅｎｇＹａｎｇ；ＸｉａｏｓｈｅｎｇＣｈｅｎ；Ｊｉ（...     

PLASTIC DEFORMATION AND DISLOCATION STRUCTURE IN γ'-PHASE OF A DIRECTIONALLY SOLIDIFIED Ni-BASE SUPERALLOY

The dislocation structure of directionally solidified(DS)Rene 80 superalloy during tensileand creep deformation has been studied by TEM.In tensile deformation,γ'shearing occurs byslip of APB-coupled(1/2)<110>dislocation pairs on{111}planes at temperatures below760℃.and by slip of SISF-seperated(1/3)<112>superpartials which have dissociated on{111}planes into a(1/2)<110>screw superpartial and a(1/6)<112>edgesuperpartial with an APB in between at temperatures equal to or above 760℃.In creepdeformation,γ'shearing occurs again by slip of SISF-seperated(1/3)<112>superpartialswhich have not dissociated on{111}planes and by diffusive slip of APB-coupled(1/2)<110>dislocation pairs at 760℃,618 MPa.However,no γ'shearing occurs at 980℃,190MPa.During secondary creep at 760℃,618 MPa or at 980℃,190 MPa,2-dimensional net-works have formed at γ/γ'interfaces,and the strain is mainly the result of diffusion control-led climb of dislocation networks at γ/γ'interfaces.The dependence of secondary creep rate εupon size a and volume fraction v_■ of cubic γ' has been found to be ■∝α/v_f~(2/3).     

MAGNETIC ACOUSTIC EMISSION CHARACTERISTICS OF HYDROGEN ATTACKED LOW CARBON STEEL

ＭＡＧＮＥＴＩＣＡＣＯＵＳＴＩＣＥＭＩＳＳＩＯＮＣＨＡＲＡＣＴＥＲＩＳＴＩＣＳＯＦＨＹＤＲＯＧＥＮＡＴＴＡＣＫＥＤＬＯＷＣＡＲＢＯＮＳＴＥＥＬ￥ＬＩＨｉａｏｇａｎｇ;ＭＥＮＧＱｉｎｇｈａｉ;ＣＨＥＮＨｕａ;ＣＨＥＮＪｉｎｗｅｉ;ＹＡＯＺｈｉｍｉｎｇ;...     

PLASTIC DEFORMATION AND DISLOCATION STRUCTURE IN γ'-PHASE OF A DIRECTIONALLY SOLIDIFIED Ni-BASE SUPERALLOY

本文利用透射电镜观察了定向凝固高温合金DS Rene80在拉伸及蠕变时的位错亚结构。试验结果表明:在低于760℃拉伸时,切割γ′粒子的是在{111}面上夹有APB的(1/2)〈110〉位错对。在不低于760℃拉伸时,切割γ′粒子的是在{111}面上夹有超点阵内禀层错(SISF)γ(1/3)〈112〉不全位错;这些不全位错在大应力的作用下于{111}面上将分解为一根(1/2)〈110〉螺位错和一根(1/6)〈112〉刃位错,并在其间夹有一个APB。在760℃,618MPa条件下蠕变时,切割γ′粒子的是在{111}面上夹有SISF的(1/3)〈112〉不全位错;这些不全位错此时不分解。与此同时,亦有(1/2)〈110〉位错对切割γ粒子。在980℃,190MPa条件下蠕变时,则无γ′粒子被切割的现象。在760℃,618MPa及980℃,190MPa条件下蠕变至第二阶段时,在γ/γ′界面上都形成了二维位错网络墙,墙上位错的攀移是合金形变的控制因素。第二阶段蠕变速率(ε)与立方γ′粒子的尺寸(α)和体积分数(V_f)的关系符合ε∝α/V_f~(2/3)     

AN IN SITU OBSERVATION OF DEFORMATION AND FRACTURE PROCESS IN METAL PART Ⅱ CLEAVAGE PROCESS IN Nb-W-Zr

<正> 本文利用扫描电镜拉伸装置对Nb-W-Zr金属的解理过程进行了观察。 研究用的金属采用200kW电子束炉二次熔炼成合金锭,先后经挤压、锻造、热轧、温轧最后精轧成厚度为0.5mm的板材。从合金板材上截取并经机加工成动态拉伸试样,放在真空炉中经1700℃,1h退火。金相抛光腐刻,腐刻剂为氢氟酸+硝酸+乳酸,比例为1:3:2,保证晶界清晰可见。     

ACTIVATION ENERGY OF FeAl ALLOYS DURING SUPERPLASTIC DEFORMATION

ＡＣＴＩＶＡＴＩＯＮＥＮＥＲＧＹＯＦＦｅＡｌＡＬＬＯＹＳＤＵＲＩＮＧＳＵＰＥＲＰＬＡＳＴＩＣＤＥＦＯＲＭＡＴＩＯＮ①ＬｉＤｉｎｇｑｉａｎｇ，ＬｉｎＤｏｎｇｌｉａｎｇ（Ｔ．Ｌ．Ｌｉｎ）ＴｈｅＰｕｂｌｉｃＬａｂｏｒａｔｏｒｙｏｆＨｉｇｈＴｅｍｐｅｒａｔｕ...     

X-RAY ANALYSIS OF WORK-HARDENING PROCESS FOR POLYCRYSTALLINE α-BRASS DURING UNIAXIAL TENSILE TESTS

X-ray diffraction Fourier profile analysis has been performed for polycrystalline α-brassplate with 31.55 wt-% Zn after a series of uniaxial tensile tests with different strain rates.Dislocation density p and configuration parameter M may be presented as a function of ap-plied stress σ_a.A mechanism of alternative long-range and short-range strain hardening hasbeen proposed.     

PHASES AND STRUCTURE OF PREFORM DURING PREPARING PROCESS OF Al／TiCp COMPOSITES BY DIRECT REACTION SYNTHESIS

ＰＨＡＳＥＳＡＮＤＳＴＲＵＣＴＵＲＥＯＦＰＲＥＦＯＲＭＤＵＲＩＮＧＰＲＥＰＡＲＩＮＧＰＲＯＣＥＳＳＯＦＡｌ／ＴｉＣｐＣＯＭＰＯＳＩＴＥＳＢＹＤＩＲＥＣＴＲＥＡＣＴＩＯＮＳＹＮＴＨＥＳＩＳＳ．ＹＺｅｎｇ;Ｂ．ＹａｎｇａｎｄＥ．Ｌ．Ｚｈａｎｇ（Ｈａｒｂｉ...     

COUPLED THERMO-MECHANICAL FEM ANALYSIS OF TWIST COMPRESSION DEFORMATION PROCESS

ＣＯＵＰＬＥＤＴＨＥＲＭＯＭＥＣＨＡＮＩＣＡＬＦＥＭＡＮＡＬＹＳＩＳＯＦＴＷＩＳＴＣＯＭＰＲＥＳＳＩＯＮＤＥＦＯＲＭＡＴＩＯＮＰＲＯＣＥＳＳ①ＸｕｅＫｅｍｉｎ，ＺｈａｎｇＺｈｅｎｇｒｏｎｇ，ＸｉａＹｏｎｇｊｉａｎｇ，ＬｕＹａｎＭｅｔａｌＦｏｒｍｉｎ...     

EFFECT OF α-PHASE MORPHOLOGY ON STRENGTHENING AND FRACTURE BEHAVIOUR OF 47121 β-Ti ALLOY

用TEM,SEM,X射线衍射及拉伸试验等研究了47121β-Ti合金的拉伸性能与α相形貌及其断裂行为的关系。结果表明,低温时效由ω相转变成的弥散α相质点,随其体积分数增加,质点间共格应力场发生交叠,产生较强的内应力,在负荷作用下,导致宏观脆断,而微观断裂机制仍属于韧窝,因此可以把局部的内应力区认为是形成精细韧窝的核心。魏氏组织的α相具有强的加工硬化效应,位错切割α相是主要强化机制,但以孪生形变的α相片阻止位错切过。晶界两侧形成的无析出带,以及随后形成的羽毛状α相群,都使晶界区弱化,导致形成类似沿晶型断口。     

CRACK NUCLEATION AND PROPAGATION IN HYDROGENATED POLYCRYSTALLINE α-Ti

用S_4-10扫描电镜的拉伸装置研究:1.α-Ti多晶体中含氢量与生长氢化物量的关系.2.充氢的α-Ti多晶体中氢化物对裂纹的萌生与扩展路径的影响.3.氢化物在形变过程中的行为.结果表明,充氢的α-Ti多晶体中生成氢化物量随含氢量增加而增多.裂纹萌生和扩展与氢化物的尺寸和分布密度有关.     

DEFORMATION AND FRACTURE OF TiAl PST CRYSTALS UNDER MONOTONIC AND CYCLIC LOADING

ＤＥＦＯＲＭＡＴＩＯＮＡＮＤＦＲＡＣＴＵＲＥＯＦＴｉＡｌＰＳＴＣＲＹＳＴＡＬＳＵＮＤＥＲＭＯＮＯＴＯＮＩＣＡＮＤＣＹＣＬＩＣＬＯＡＤＩＮＧＹ．Ｕｍａｋｏｓｈｉ；Ｔ．ＮａｋａｎｏａｎｄＨ．Ｙ．Ｙａｓｕｄａ（ＤｅｐａｒｔｍｅｎｔｏｆＭａｔｅｒｉａｌｓＳｃ...     

CYCLIC DEFORMATION OF FCC CRYSTALS AND ITS DISLOCATION INTERACTION MODEL Ⅱ. DISLOCATION INTERACTION MODEL OF CYCLIC DEFORMATION

运用位错之间的交互作用理论,对各种轴向Cu晶体的循环形变行为进行了分析和比较,确认晶体循环形变的应力-应变响应以及形成的位错组态是由各滑移系统的位错反应的模式和强度决定的,根据晶体轴向在标准取向三角形中的位置,可以推断其循环形变行为.     

COMBINATION STRENTHENING PROCESS OF Ni-W-Ti-SiC COMPOSITE COATING AND NITROCARBURIZATION

ＣＯＭＢＩＮＡＴＩＯＮＳＴＲＥＮＴＨＥＮＩＮＧＰＲＯＣＥＳＳＯＦＮｉＷＴｉＳｉＣＣＯＭＰＯＳＩＴＥＣＯＡＴＩＮＧＡＮＤＮＩＴＲＯＣＡＲＢＵＲＩＺＡＴＩＯＮ①ＭａＫｅｙｉ，ＧｕｏＺｈｏｎｇｃｈｅｎｇ，ＷｅｎＭｉｎｇｆｅｎ，ＹａｎｇＸｉａｎｗａｎＤ...     

ON THE VOID GROWTH OF C-Mn STRUCTURAL STEEL DURING PLASTIC DEFORMATION——Ductile Fracture Mechanisms in a Structural Steel (Ⅱ)

在试验分析的基础上,本研究提出了一种程序,以建立C-Mn结构钢在韧性断裂过程中的空穴增长与塑性应变及三轴应力状态之间的关系,并确定了空穴增长系数。由光滑拉伸试样和预制裂纹侧槽三点弯曲试样试验所确定的空穴增长系数,可能适宜较宽的试样拘束变化范围。空穴增长的实验关系式表明,当三轴应力状态(σm/(?))约大于1.2时,在该结构钢中的实际空穴增长速率低于由Rice-Tracey理论所确定的空穴增长速率,然而当三轴应力状态(σm/(?))约小于1.2时,由Rice-Tracey理论所确定的空穴增长表现为对实际材料中的空穴增长估计略为不足。另外,根据实验空穴增长研究,对预制裂纹侧槽三点弯曲试样在韧性起裂时钝化裂纹前端的塑性应变、相对空穴体积和应力状态三轴性的变化进行了测量和估计。     

CYCLIC DEFORMATION OF FCC CRYSTALS AND ITS DISLOCATION INTERACTION MODEL Ⅰ. CYCLIC DEFORMATION OF COPPER SINGIE CRYSTALS

系统地观察了各种不同轴向Cu晶体的循环应力-应变响应及其饱和位错结构.实验结果表明,晶体的宏观循环形变行为和微观位错组态的演变都与晶体的轴向紧密相关.在一些轴向位于标准取向三角形内的单滑移晶体中观察到明显的多滑移现象;其循环形变行为和饱和位错结构都与相邻的双滑移或多滑移晶体有许多相似之处.