摘要：磨擦搅动(FSW ) 焊接是一种创新稳固的州的加入技术并且在太空，栏杆，为加入铝的汽车、海洋的工业，镁，锌和铜被采用了合金。FSW 过程参数象工具那样旋转速度，焊接速度，轴的力量，在决定焊接质量起一个主要作用。二个方法，反应表面方法论和人工的神经网络被用来预言磨擦的张力的强度搅动焊接 AA7039 铝合金。实验基于三个因素被进行，三水平、中央的合成的脸与完整的复制技术集中了设计，并且数学模型被开发。敏感分析被执行识别批评参数。通过反应表面方法论获得的结果与通过人工的神经网络的那些相比。

摘要：In many circumstances,dissimilar metals have to be bonded together and the resulting joint interfaces must typically sustain mechanical and/or electrical forces without failure,which is not possible by fusion welding *** melting points of magnesium(Mg)and copper(Cu)have a significant difference(nearly 400℃)and this may lead to a large difference in the microstructure and joint performance of Mg-Cu ***,diffusion bonding can be used to join these alloys without much *** work analyses the effect of parameters on diffusion layer thickness,hardness and strength of magnesium-copper dissimilar *** experiments were conducted using three-factor,five-level,central composite rotatable design *** relationships were developed to predict diffusion layer thickness,hardness and strength using response surface *** is found that bonding temperature has predominant effect on bond *** fabricated at a bonding temperature of 450℃, bonding pressure of 12 MPa and bonding time of 30 min exhibited maximum shear strength and bonding strength of 66 and 81 MPa, respectively.

摘要：The main objective of this investigation is to study the influence of arc constriction current frequency(ACCF)on tensile properties and microstructural evolution of aerospace Alloy 718 sheets(2 mm in thickness)joined by constricted arc TIG(CA-TIG)welding *** variable at a time approach of design of experiments(DOE)was used,in which ACCF was varied from 4 to 20 kHz at an interval of 5 levels while other parameters were kept *** joints welded using ACCF of 4 kHz exhibited superior tensile properties extending joint efficiency up to 99.20%.It is attributed to the grain refinement in fusion zone leading to the evolution of finer,discrete Laves phase in interdendritic *** increase of ACCF above 12 kHz caused severe grain growth and evolution of coarser Laves phase in fusion *** 718 welds showed more obvious tendency for Nb segregation and Laves phase formation at higher levels of ACCF due to the slower cooling *** volume fraction of Laves phase was increased by 62.31%at ACCF of 20 kHz compared to that at 4 kHz,thereby reducing the tensile properties of *** is mainly due to the stacking of heat input in weld thermal cycles at increased levels of ACCF.

摘要：An attempt was made to optimize friction welding parameters to attain a minimum hardness at the interface and a maximum tensile strength of the dissimilar joints of AISI 304 austenitic stainless steel （ASS） and copper （Cu） alloy using response surface methodology （RSM）. Three-factor, five-level central composite design matrix was used to specify experimental conditions. Twenty joints were fabricated using ASS and Cu alloy. Tensile strength and interface hardness were measured experimentally. Analysis of variance （ANOVA） method was used to find out significant main and interaction parameters and empirical relationships were developed using regression analysis. The friction welding parameters were optimized by constructing response graphs and contour plots using design expert software. The developed empirical relationships can be effectively used to predict tensile strength and interface hardness of friction welded ASS-Cu joints at 95% confidence level. The developed contour plots can be used to attain required level of optimum conditions to join ASS-Cu alloy by friction welding process.

摘要：Empirical relationship was developed to predict the fatigue life of gas metal arc welded （GMAW） cruciform joints failing from root region. High strength, age hardenable aluminium alloy of AA7075-T6 grade was used as the base material. The design of experiments concept was used to optimize the required number of fatigue testing experiments. Fatigue experiment was conducted in a servo hydraulic controlled fatigue testing machine under constant amplitude loading. The empirical relationship was developed. By using the developed empirical relationship, the fatigue life of GMAW cruciform joints failing from root region was predicted at 95% confidence level. The effect of cruciform joint dimensions on fatigue life was discussed in detail.