共查询到20条相似文献,搜索用时 31 毫秒
1.
T.Y.Hsu 《金属学报(英文版)》1991,4(6):401-406
An approach for the thermodynamics of the thermoelastic martensitic transformation in β-Cu base alloys is suggested.Driving forces for martensitic transformation,T_0 and M_s tempera- tures in Cu-Zn,Cu-Al and Cu-Zn-Al alloys were calculated and the calculated M_s are in good agreement with the experimental ones.Ordering of the parent phase lowers M_s(T_0)in Cu-Zn and Cu-Zn-Al alloys,but raises M_s(T_0)in Cu-Al alloys.Two methods for the es- timation of the critical driving force for the thermoelastic martensitic transformation are also introduced. 相似文献
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PAN Mu XU Zuyao 《金属学报(英文版)》1990,3(3):153-157
The M_s temperature and the yield strength of austenite at M_s temperature have been meas-ured for five Fe-Mn-C alloys.The experimental results show that there is a linear relation-ship between them.The effect of the solution strengthening of austenite on martensitemorphology is also studied.It is pointed out that there is a characteristic temperature T_c inaustenite strengthening.Martensite morphology is mainly of dislocated laths when M_s>T_c,and is mainly of twinned plates when M_s相似文献
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YIN Hong TAO Kun PAN Jinsheng LI Hengde Tsinghua University Beijing China professor.Department of Materials Science Engineering Tsinghua University Beijing China 《金属学报(英文版)》1993,6(3):145-152
The critical _d vahues ( _ ) of the γ/(γ+σ).γ/(γ+μ) and γ/(γ+γ') phase boundaries insome ternar alloy phase diagrams at various temperatures are calculated by averaging the _d values of sererai selected characteristic points at the phase boundaries.Approxmateequations for the temperature dependence of the critical _d of γ/(γ+σ).γ/(γ+μ) andγ/(γ+γ') phase boundaries are established.The accuracy of the analysis is discussed in detail.It is found for the first time that the average value of the bondorder _ at the phase boundaries ts also approximatelr a constant and therefore a criticalaverage bond order _ like - can be introduced for the analysts of phase stability 相似文献
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CHU Wuyang XIAO Jimei University of Science Technology Beijing Beijing ChinaTHOMPSON AW Carnegie Mellon University U.S.A 《金属学报(英文版)》1992,5(4):286-291
Both hydrogen induced cracking and overload crack initiated at same characteristic distance,r~*,within the plastic zone along the slip line when the plastic zone developed to a critical ex-tent.For the overload crack.K_(IC)=αr~*~(1/2)[σ_F~((n+1)/2n)/σ_(ys)~((1-n)/2n)],σ_F=σ_0+g[2μbσ_(th)/π~2L(1-v)]~(1/2)For the hydrogen induced cracking:K_(IH)=αr~*~(1/2)[σ_F(H)~((n+1)/2n)/σ_(ys)(H)~((1-n)/2n)],σ_F(H)={σ_0(H)+g[2μbσ_(th)(H)/π~2L(1-v)]~(1/2)}/kHydrogen pomoting the dislocation multiplication and motion would result in σ_0(H)<σ_0,k>1,Therefore,hydrogen promoting the cleavage fracture in titanum aluminide can be dueto that hydrogen facilitates the local plastic deformation,which results in σ_F(H)<σ_F and thenK_(IH)相似文献
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XU Zuyao 《金属学报(英文版)》1992,5(6):465-467
Two driving forces △G~((β_1)+α')and △G~(β_1→β_2+α)for the bainitic transformation have been calcu-lated for Cu-24 at.-% Al alloy.Results reveal △G~(β_1→α')>0 within the transformation tem-perature range 600—750 K.Therefore,the bainitic transformation cannot be initiated by theβ_1→α' shearing mechanism.On the other hand,the driving force △G~(β_1→β_2+α)to produce 5% ofthe α becomes negative only when the composition of the α satisfiesx_(Al)~α≤0.204 at 700 K or x_(Al)~α=0.209 at 750 K.So the bainitic transformation can only proceedby β_1→β_2+α diffusional reaction with different diffusion amount at different temperatures. 相似文献
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采用水冷铜模吸铸工艺制备了一系列的(Fe0.5Co1-xNix)72B19.2Si4.8Nb4(x=0,0.05,0.1,0.15,0.2,0.25,0.3,0.4)块体非晶合金.并采用X射线衍射仪(XRD)、差热分析仪(DTA)、振动样品磁强计(VSM)测试了块体非晶合金的结构、热稳定性和软磁性能.探讨了不同Ni/Co比例及添加稀土元素Dy对FeCoNiBSiNb系合金玻璃形成能力(GFA)、热稳定性及磁性能的影响.结果表明:当x=0.05,0.1,0.15,0.2时可制备出直径2mm的非品合金棒,但不能获得3mm非晶合金棒,x=0.25,0.3,0.4均不能获得直径2mm的非晶合金棒,且随Ni/Co比例的增大,即随Ni含量的增加,热稳定性先增加,后逐渐减小,过冷液相区△Tx逐渐减小,非晶合金的玻璃形成能力呈下降趋势,非晶合金的饱和磁化强度(Ms)下降.添加1 at%Dy后,提高了合金的非晶形成能力,可制备出直径3mm的[(Fe0.5Co0.4Ni0.1)72B19.2Si4.8Nb4]99Dy1非晶合金棒,但合金的Ms下降. 相似文献
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ZHANG Derong Shenyang Institute of Aeronautical Engineering Shenyang China ZHANG Derong Associate Professor.Dept.of Aeronautics Shenyang Institute of Aeronautical Engineering Shenyang China 《金属学报(英文版)》1990,3(9):196-199
An attempt was made on the quantitative prediction of the relationship hetween the yieldstress and R-value along the parallel and perpendicular to the rolling direction of Ti platebased on analysis of the previous experimental data.It is shown that the yield stress along onedirection and another is quite synchronized with the R—value.According to the plasticity theo-ry,an formular of σ_(1s)/σ_(2s)=[(1+1/R_2)/(1+1/R_1)/~(1 2) was proposed,In statistic estima-tion.the calculated results are in good agreement with the experimental data.The availabilityof this formula was briefly discussed also. 相似文献
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含硼的Cu—Zn—Al合金中母相晶粒度和有序度对Ms的影响 总被引:7,自引:0,他引:7
研究了母相平均晶粒尺寸和有序度对Cu-25.62Zn-3.97Al-0.0018B(wt-%)形状记忆合金热弹性马氏体相变点的影响。从相变热力学出发,得到马氏体相变点和晶粒尺寸的平方根的倒数成线性关系,并且随晶粒尺寸增大,马氏体相变点升高,与电阻法测得的结果符合很好。运用Landau理论,得到马氏体相变点和母相有序度的定量关系式,与X光衍射和电阻法试验的结果符合较好。求得试验用合金母相DO_3有序化的激活能约为46kJ/mol。 相似文献
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WU Jianzhong WANG Changzhen Northeast University of Technology Shenyang China Professor Dept.Non-ferrous Metallurgy Northeast University of Technology Shengyang China 《金属学报(英文版)》1989,2(7):1-7
The activity of CaO and La_2O_3 in the liquid ternary slay CaO-SiO_2-La_2O_3 has been de-termined by equilibrating Sn with the slag phase in a graphite crucible under l arm of CO at1600C.The experimental results ,showed that the activity of CaO and La_2O_3 changes slowlywhile the ratio of mole fraction.x_(CaO)/x_(SiO_2),is less than unit.hut varies sharply while the ra-rio increases from 1 to 1.2.In addition,by equilibrating Sn with the binary slagB_2O_3-La_2O_3 saturated witlt solid La_2O_3 at three different temperatures,the relation betweenIgγ_(La)~0 and I/T is determined as follows:Igγ_(La)~0=-20400/T+11.37(1500-1600C)A random network model of molten silicate structure was applied to CaO-SiO_2-La2O_3.It was found that the experimentally determined activity-composition curve of CaO arequalitatively reproduced by the curves calculated with the model,but the curves of La_2O_3 areconsiderahly different from the calculated ones.It implies that the model used is over-simpli-fied and that the difference in interaction energy between the metal cations of different valenceand silicate anions should be considered. 相似文献
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阐明了TC4钛合金电子束焊接接头相变的热力学特征,从热力学角度分析了TC4钛合金电子束焊接接头在不同的热处理条件下形成不同组织结构的机制,为通过改变热处理制度控制TC4钛合金电子束焊接接头相变的方法,提供了理论基础.结果表明,TC4钛合金电子束焊接接头的相变驱动力来源于新相马氏体和母相的化学自由能差,形成的马氏体贯穿整个晶粒,并且其取向呈一定的角度;低于MS点的焊后热处理只能使马氏体长大,而高于MS点的焊后热处理不仅使马氏体长大,还使部分β相成为饱和固熔体,并残留在马氏体片层之间. 相似文献
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微量稀土Dy及Fe/Co比例对FeCoBSiNb块体非晶合金玻璃形成能力和磁性能的影响 总被引:2,自引:2,他引:0
采用铜模吸铸工艺成功制备了一系列的[(Fe_xCo_(1-x))_(0.72)B_(0.192)Si_(0.048)Nb_(0.04)]_(100-y)Dy_y(x=0.5,0.6,0.7,0.8,0.9;y= 0,1,2,3)块体非晶合金,并采用X射线衍射仪(XRD)、示差扫描量热分析仪(DSC)、振动样品磁强计(VSM)测试块体非晶合金的结构、热稳定性和软磁性能;分析了稀土元素Dy以及不同Fe/Co比例对FeCoBSiNb系合金玻璃形成能力(GFA)、热稳定性及磁性能的影响。结果表明:添加2at%的Dy后,合金的非晶形成能力提高,可制备出φ3mm的[(Fe_(0.5)Co_(0.5))_(0.72)B_(0.192)Si_(0.048)Nb_(0.04)]_(98)Dy_2非晶合金棒,但合金饱和磁化强度(M_s)下降;[(Fe_xCo_(1-x))_(0.72)B_(0.192)Si_(0.04)8Nb_(0.04)]_(98)Dy_2非晶合金随Fe/Co比例从5∶5增加至8∶2时,均能形成φ2 mm的非晶棒,但合金的非晶形成能力呈下降趋势,而其饱和磁化强度随铁含量的增大而提高。 相似文献
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MATHEMATICAL MODELS OF NITROGEN CONCENTRATION PROFILE OF ION NITRIDED LAYERS AND COMPUTER SIMULATION 总被引:1,自引:0,他引:1
XIA Lifang YAN Mufu Harbin Institute of Technology Harbin China Laboratory of Metal Materials Heat treatment Harbin Institute of Technology Harbin China 《金属学报(英文版)》1989,2(7):18-26
The mathematical models of the kinetics of the layer growth at different ion nitriding condi-tions of armco iron.steels 45,40Cr,42CrMo and 38CrMoAl have been established.Based onthese models the expression of nitrogen concentration profile of ion nitrided layers have beendeduced with profile simulating method.They areC_=C_(min)~+(P_4)/(ξ_1-x)+(P_5)/(ξ_(10)~2)(ξ_1-x)~2C_(γ′)=C_(min)~(γ′)+(P_1)/(ξ_(21))(ξ_2-x)+(P_2)/(ξ_(21)~2)(ξ_2-x)~2C_α=C_(min)~α+(C_(33))/(C_(33))/(ξ_(32))(ξ_3-x)~3Using these models,the kinetics of layer growth and the nitrogen concentration profile of ionnitrided layers were sinulated on Apple-Ⅱ computer.Results show that the simulated curvescoincide quite well with the experimental data. 相似文献
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WU Jianxin JIANG Bohong XU Zuyao 《金属学报(英文版)》1989,2(5):326-332
The effect of grain size and ordering of the parent phase on the critical points of thermoelasticmartensitic transformation in Cu-25.62 Zn-3.97 Al-0.0018 B(wt-%)shape memory alloyhas been investigated.Based on the thermodynamics of phase transformation,a linear rela-tionship between the starting temperature of martensitic transformation and the reciprocal ofthe square root of grain size is obtained,i.e.M_s temperature rises with increasing grain size.It shows a good agreement with the results of electric resistance measurement.Applying theLandau's theory,a quantitative relationship between M_s and the ordering parameter of theparent phase is set up,which is well confirmed by the results of X-ray diffraction and electricresistance measurement.The activation energy of the ordering process in the parent phase ofthe alloy is calculated to be 46 kJ/mol. 相似文献
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采用OM,SEM,EDS,EPMA等分析手段对试制的镍基合金焊丝GTAW熔敷金属开展了凝固偏析行为研究.结果表明,熔敷金属中主要包括γ相、(Nb,Ti) C碳化物、Laves相等,金相组织主要为柱状晶,在枝晶间存在宽度约为5~10 μm的偏析区域;按照Scheil公式对EPMA分析结果进行了偏析系数计算,估算的Nb,Mo,Ni,Cr,Fe偏析系数分别为kNb=0.23,kMo=0.68,kNi=1.07,kCr=1.05,kFe=1.23,在结晶过程中Nb,Mo更倾向于分配在残余液相,Nb的偏析倾向最大,Mo次之,Fe更倾向于分配在固相中,Ni,Cr基本为固液平均分配.文中试验用镍基合金焊丝GTAW熔敷金属凝固结晶路径为L→L+γ→L+γ+MC→L+γ+MC+Laves相→γ+MC+Laves相. 相似文献
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XIE Changsheng SUN Peizhen ZHAO Jiansheng CHEN Yuqiu Huazhong University of Science Technology Wuhan China XIE Changsheng Associate Professor Department of Mechanical Engineering No. Huazhong University of Science Technology Wuhan China 《金属学报(英文版)》1990,3(1):52-57
The microstructures of Fe-Mn-Ni-Cr steels with medium carbon and the effect of alloy ele-ments on them have been investigated by means of X-ray diffraction quantitative phase ana-lyses,metallography and hardness tests.The volume fraction of martensite in steels quenchedat 1100℃ can be expressed as:f_M~(1100)=162.643-15.482Mn-7.36Ni-4.286(Cr+Mo+V)Based on this expression,the quasi-equilibrium microstructure diagram has been obtained.Itis shown that the effect of Mn on the austenite stability is greater than that of Ni.The equiva-lent [Ni]=2.104Mn+Ni and equivalent [Cr]=Cr+Mo+V.The driving force for martensite transformation at M_s point has been calculated to hedrastically decreased by element Mn. 相似文献
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LIN Guangming HUANG Yuanshi ZHANG Jinxiu Zhongshan University Guangzhou China LIN Guangming Associate Professor Dept.of Physics Zhongshan University Guangzhou China 《金属学报(英文版)》1990,3(3):164-169
The snap-acting transition and two way shape memory (TWSM) effect have been obtainedin a TWSM spring made of Ni51Ti49 alloy using the constrained effect of stress on drivingforce of TWSM material.When the snap-acting transition has been realized:M_s= M_f andA_s=A_f;hysteresis is rectangular,the height (TWSM effect) and width (hysteresis) of therectangle can be readjusted by means of constrained stress.The results of resistancemeasurments show that,the snap-acting TWSM effect mentioned above was supplied mainlyfrom the transformation of P←→R.The thermodynamic model has also been proposed to ac-count for the snap-acting transformation. 相似文献