摘要:

AbstractA continuous SiC fibre reinforced Ti–6Al–4V composite was diffusion bonded to itself. Incorporation of a Ti–6Al–4V interlayer and use of an etching treatment to smooth the faying surface improved the diffusion bondability of the composite. The bond strength increased with bonding time up to 10·8 ks under 10 MN m−2pressure at 1173 K, at which time, after reaching the maximum value of approximately 700 MN m−2, the strength was saturated. Corresponding to this behaviour, the bonding between the interlayer and the composite matrix was completed after a bonding time of 10·8 ks. Bonding between the fibre and the interlayer was considered not to contribute to the joint strength on the basis of observation of the fracture surfaces. The bond strength therefore seems to be controlled by the bonding of the interlayer and the composite matrix.MST/1568

ISSN:0267-0836    

DOI:10.1179/mst.1992.8.9.811

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

AbstractThe microstructures resulting from the reaction between gold and Pb–Sn solder at temperatures of 80, 125, 140, and 160°C have been studied in the scanning electron microscope and measurements have been made of the reaction kinetics. In the initial stages, the growth rate of the layers of Au–Sn intermetal1ic product was found to be proportional to t1/2with an activation energy of (0·84±0·02) eV. At longer times, the growth rate fell below the t1/2dependence. This was thought to be owing to a restriction in the supply of gold to the reaction.MST/1599a

ISSN:0267-0836    

DOI:10.1179/mst.1992.8.9.817

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

AbstractSputtered Ni–TiB2coatings have been shown to protect Ti–6Al–4V and Inconel 718 substrates from solid particle erosion. However, before new erosion resistant coatings can be efficiently designed, it is essential that the role of mechanical properties in determining erosion resistance be fully understood. In this investigation, nanoindentation techniques were used to quantify the effects of substrate preparation, coating composition, and sputtering process parameters on the elastic moduli and indentation hardness of thin coatings deposited on Ti–6Al–4V and Inconel 718 substrates. The influence of these parameters on coating adhesion was determined using a conventional scratch test. Elastic moduli, indentation hardnesses, and coating adhesion were correlated with erosion behaviour. The erosion resistance of the coatings that exhibited microscopic ductility is dependent on the nodule diameter and coating properties such as hardness, elastic modulus, and fracture toughness.MST/1697

ISSN:0267-0836    

DOI:10.1179/mst.1992.8.9.825

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

AbstractThe aim of this study was to verify the mechanism of parallel heat welding (PHW) and to investigate the thermal and residual stresses due to welding. In this study, autogenous gas tungsten arc welding was used on type 304 stainless steel. Wells' one-dimensional stress distribution model was assumed to explain the behaviour of stress introduced by conventional welding (CW) and PHW processes. A step by step method proposed by Tall was applied to calculate theoretical thermal and residual stresses. Comparison between experimental and analytical results showed that the predicted results calculated using a modified Wells' model are in agreement with the experimental results, and that the elevation of equilibrium temperature during the welding process is an important mechanism for the reduction of residual stress in the PHW process. The theoretical curves of residual stress calculated for thermal cycles corresponding to CW and PHW processes show fairly good agreement with experimental results in the vicinity of the fusion zone.MST/1552

ISSN:0267-0836    

DOI:10.1179/mst.1992.8.9.837

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

AbstractA model for calculating the temperature field in submerged arc welding is presented. The algorithm is based on the method of elementary balances. Melting of the electrode rod and melting of the parent material followed by solidification of the pool of molten metal are considered. The calculated temperature evolution curves are compared with the results of experiments. The temperature evolutions at characteristic points of a welded joint are shown.MST/1289

ISSN:0267-0836    

DOI:10.1179/mst.1992.8.9.841

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

ISSN:0267-0836    

DOI:10.1179/mst.1992.8.9.844

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor