THE m-C-δ OR m-k-δ RELATIONS OF SUPERPLASTICITY OF Zn-5%Al EUTECTIC ALLOY

在170,190,210,230,250℃的温度下,采用3.7×10~2,7.4×10~2和1.1×10~(-1)min(-1)的应变速率(平均)对Zn-5%Al共晶合金的m-C-δ(或m-k-δ)关系曲线(简称m-δ关系曲线)进行了测定.所有的曲线均随应变的δ增加而快速上升.俟达到某一定的应变量(极限应变量δ1)后。开始缓慢下降并保持平稳直至断裂.Zn-5%A1共晶合金的m-δ关系曲线不存在k_(?)=k_I(k_(I 1),k_(I 2),k_(I 3),……)=k_F(或C_0=C_I(C_(I 1),C_(I 2),C_(I 3),……)=C_F=1)的简单情况.可应用m-δ方程式[4,5]对曲线上各点C值(包括所有的C_I和C_F值)进行计算.C值随δ值的增加成近似的直线上升.直线的斜率在极限应变(δ1)处突然减小.     

SUPERPLASTICITY OF A RAPIDLY SOLIDIFIED AI-Li ALLOY

A rapidly solidified microcrystalline Al-Li-Cu-Mg-Zr alloy and its superplasicity have beeninvestigated.An optimum tensile elongation of 585% was obtained at 540℃ and strain rate1.67×10~(-2)s~(-1).The superplastic Al-Li alloy is manufaetured using thermomechanical pro-cessing:solution,overaging,warm rolling and recrystallization.Microstructural changes inthermomechanical processing and cavitation occurred during superplastic deformation havebeen observed.The superplastic failure of alloy may be caused mainly by nucleation andgrowth of cavities as well as the linkage around grains.     

ANALYSIS OF TWO PRINCIPAL FACTORS AFFECTED ON m-δ RELATIONS

本文对影响m-δ关系散乱的两个主要因素,m值变化及初始不均匀的差异进行了分析.给出了包含m值变化的,m-δ关系式和包含初始力学缺陷的m-δ关系式.并证明在超塑性状态(n=0)两种初始不均匀(几何不均匀和力学不均匀)存在某种等效关系.考虑到m值变化和初始不均匀的差异,理论计算曲线能够包含相当数量合金的实验结果.     

SUPERPLASTICITY OF A WATER-QUENCHED AND TEMPERED 40Cr STEEL

1.IntroductionSuperplasticity possesses many good characteristics such as high elongation, low flow stress and high atom diffusion ability, which make it show good application in metal forming and diffusion bonding of complex shape structure. Up to now, the superplasticity of steel has been more investigated, however the pretreatment in order to obtain fine grain and then superplasticity was often carried out by circular quenchingof typically 3 times and subsequent high-temperature tempering, …     

APPROXIMATE MEANS FOR EVALUATING TENSILE STRENGTH OF HIGH POROSITY MATERIALS

１ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｔｅｎｓｉｌｅｓｔｒｅｎｇｔｈｉｓａｎｉｍｐｏｒｔａｎｔｐｒｏｐｅｒｔｙｆｏｒｅｎｇｉｎｅｅｒｉｎｇｍａｔｅｒｉａｌｓ，ａｎｄｔｈｅｓａｍｅｆｏｒｔｈｅｐｏｒｏｕｓｏｎｅｓ，ｓｏｐｅｏｐｌｅｈａｖｅｂｅｅｎｔｈｉｎｋ...     

SUPERPLASTICITY BEHAVIOURS OF Ni_3Al ALLOY WITH 10-30μm GRAIN SIZES

研究了晶粒尺寸为10—30μm的Ni3Al基合金的高温变形行为发现该合金在950—1100℃温区，应变速率约为2．1×10-4s-1时应变速率敏感指数m＞0．3，最大延伸率超过250％，具有超塑变形行为的特征金相及电子显微镜观察表明，变形过程中发生了明显的连续回复与再结晶．     

A MATHEMATICAL EXPRESSION OF CRYSTAL GROWTH RATE DURING CRYSTALLIZATION OF AMORPHOUS ALLOYS

A mathematical expression of the crystal growth rate during crystallization of the amorphousalloys was derived from the micromechanism of crystallization newly developed by theauthors. Thus, the satisfactory explanation of the experimental results obtained by Nunogakiet al., Heimendahl et al. and the authors might be found. It seems also to be modelled with theexpression for the crystal growth and the crystal size influenced by time during thecrystallization of amorphous Ni-P alloy foil at in situ heating. Based on the expression, thefactors influencing the crystal growth rate, such as temperature, time and microstructure ofamorphous alloys have been discussed.     

SUBSTRATE MATERIALS FOR POLY-CSiTF SOLAR CELLS： OPTIMIZATION OF SILICON SHEET FROM POWDER

1.IntroductionIn recentyearspolycrystalline silicon thin film solarcells(poly-CSiTF)have attracted m ore andm ore attention foritsrelative high conversion efficiency and low costprospect.The costofsilicon m ate-rialtakesone third ofthe totalcostofw afer-b…     

THEORY OF DYNAMIC OPTIMIZATION FOR MATERIALS HEATING PROCESS——CRITERION RESTRAINING METHOD

A criterion restraining mehod adopted to the dynamic optimization for materials heat-ing process has been developed,by regarding it as controlled object of a regulator incontrol theory and combining the optimal criterion of it.The method may be availableto optimize fuel supply along furnace length and to provide a theoretical basis for theoptimization of fuel supply in time-varying.For soaking pit,the calculation shows thatin case of optimization by criterion restraining method,the thermal efficiency is 3.1higher than the modelling prediction result.In comparison with heat flux-decomposingmethod,the thermal efficiency increased from 43.1 to 43.8%,and the energy consumptionwas reduced by 7.28% relative to the practical production data.     

SUPERPLASTICITY OF A SiC_w/2024 Al COMPOSITE MADE BY PRESSURE INFILTRATION

The superplastic characteristics of the β-SiC whisker reinforced 2024 aluminum composite, fabricated by pressure infiltration and hot-rolling after extrusion, were investigated. The composite has a fine grain size of about 1μm, and exhibits a maximum tensile elongation of 370% in the initial strain rate of 3.3×10-3s-1 at 788K.The superplastic deformation mechanism of the composite is thought to be grain boundary (interface) sliding accommodated by grain boundary diffusion of aluminum atom and an appropriate amount of liquid phase.     

CONTACT MATERIALS FOR GaSb AND InSb: A PHASE DIAGRAM APPROACH

1. IntroductionAmong the III-V compound semiconductors, GaSb and InSb, belong to the narrowbandgap materials which gained increasing interest during the last yearsIl,2l due to theirhigh potentiality for many electronic and optoelectronic aPplications. The…     

SLIP LINE METHOD FOR SINTERED POWDER MATERIALS UNDER CONDITION OF AXIAL SYMMETRY DEFORMATION

Slip line method for sintered powder materials under condition of axial symmetry is proposed based on the simplified yield condition of sintered powder materials and Haar-von Karman perfect plastic criterion. The equations of slip line and stress along slip line are derived, and numerical solutions are given. Deformation load in closed die upsetting of sintered copper cylinder is calculated by slip line method, and theoretical solutions are compared with experimental results.     

THEORY OF DYNAMIC OPTIMIZATION FOR MATERIALS HEATING PROCESS——CRITERION RESTRAINING METHOD

通过把物料的加热过程视作控制理论中调节器的最优控制对象,结合物料加热过程的最优准则,建立了准则约束的优化方法,利用这一方法不仅可以解决物料加热的分布供热的优化问题,而且也为时变供热问题的优化提供了理论依据,这种方法在均热炉上应用的结果表明:与钢锭加热过程预示模型的计算结果相比,优化后热效率可提高3.1％;与热流分解的优化方法相比、热效率从43.1％提高到43.8％;与实际加热过程相比,可降低能耗7.28％。     

A NEW ORTHOTROPIC YIELD FUNCTION DESCRIBABLE ANOMALOUS BEHAVIOR OF MATERIALS

ＡＮＥＷＯＲＴＨＯＴＲＯＰＩＣＹＩＥＬＤＦＵＮＣＴＩＯＮＤＥＳＣＲＩＢＡＢＬＥＡＮＯＭＡＬＯＵＳＢＥＨＡＶＩＯＲＯＦＭＡＴＥＲＩＡＬＳＡＮＥＷＯＲＴＨＯＴＲＯＰＩＣＹＩＥＬＤＦＵＮＣＴＩＯＮＤＥＳＣＲＩＢＡＢＬＥＡＮＯＭＡＬＯＵＳＢＥＨＡＶＩＯＲＯＦ...     

APPLICABILITY OF QUASICHEMICAL MODEL FOR SOME LIQUID ALLOYS WITH STRONG-INTERACTED COMPONENTS

ＡＰＰＬＩＣＡＢＩＬＩＴＹＯＦＱＵＡＳＩＣＨＥＭＩＣＡＬＭＯＤＥＬＦＯＲＳＯＭＥＬＩＱＵＩＤＡＬＬＯＹＳＷＩＴＨＳＴＲＯＮＧＩＮＴＥＲＡＣＴＥＤＣＯＭＰＯＮＥＮＴＳ①ＬｉＪｉａｎｆｅｎｇ，ＤｅｎｇＨｏｎｇｍｅｉ，ＣｈｅｎＮｉａｎｙｉＳｈａｎｇｈａｉ...     

INTERACTION OF PARTICLES WITH A SOLIDIFIED INTERFACE DURING SOLIDIFICATION OF METAL MATRIX COMPOSITE REINFORCED WITH PARTICLES

ＩＮＴＥＲＡＣＴＩＯＮＯＦＰＡＲＴＩＣＬＥＳＷＩＴＨＡＳＯＬＩＤＩＦＩＥＤＩＮＴＥＲＦＡＣＥＤＵＲＩＮＧＳＯＬＩＤＩＦＩＣＡＴＩＯＮＯＦＭＥＴＡＬＭＡＴＲＩＸＣＯＭＰＯＳＩＴＥＲＥＩＮＦＯＲＣＥＤＷＩＴＨＰＡＲＴＩＣＬＥＳＣＨＵＳｈｕａｎｇｊｉｅ;Ｗ...     

A PARAMETER FOR EVALUATING ABILITY OF GRAIN REFINEMENT OF SOLUTE ELEMENTS

The gradient of the equilibrium melting temperature distribution at the advancing liquid-solidinterface of liquid side was derived.From which,a parameter,H,used for evaluating the abili-ty of grain refinement of solute elements was proposed.Experiments on Al-based alloys showthat the grain size decreases as the value of parameter,H,increases.Such a dependance indi-cates that the parameter H can be used for choosing grain refiner.     

DEVELOPMENT OF A NEW GENERATION OF ADDITIVES FOR ALUMINIUM ROLLING LUBRICATION

ＤＥＶＥＬＯＰＭＥＮＴＯＦＡＮＥＷＧＥＮＥＲＡＴＩＯＮＯＦＡＤＤＩＴＩＶＥＳＦＯＲＡＬＵＭＩＮＩＵＭＲＯＬＬＩＮＧＬＵＢＲＩＣＡＴＩＯＮＭａｏＤａｈｅｎｇ；ＸｉａｏＧａｎｇ；ＭａＷｅｎｈｏｎｇ（ＣｏｌｌｅｇｅｏｆＥｌｅｃｔｒｏ－ｍｅｃｈａｎｉｃａｌＥ...     

A NEW METHOD FOR CLASSIFICATION OF ROCK DRILLABILITY

A New method of rock drillability classification for impregnated diamond drilling is recommended. The essence of the method is comparing the area of the slots cut respectively on a standard synthetic rock sample and the rock sample being classified by one diamond saw to determine the rock drillability in diamond core drilling. This method has the advantages of good in simulation and stable in comparison standard.     

MODELING OF SUPERPLASTIC FORMING PROCESS FOR ALUMINUM ALLOYS WITH STRAIN HARDENING EFFECT

ＭＯＤＥＬＩＮＧＯＦＳＵＰＥＲＰＬＡＳＴＩＣＦＯＲＭＩＮＧＰＲＯＣＥＳＳＦＯＲＡＬＵＭＩＮＵＭＡＬＬＯＹＳＷＩＴＨＳＴＲＡＩＮＨＡＲＤＥＮＩＮＧＥＦＦＥＣＴＹ．Ｎ．ＫｗｏｎａｎｄＹ．－Ｗ．Ｃｈａｎｇ（ＣｅｎｔｅｒｆｏｒＡｄｖａｎｃｅｄＡｅｒｏｓｐａｃ...