Samples of Ti-3Al-5V-5Mo alloy were compressed in both b and aqb phase region on a Gleeble 1500 Simulator. Compression tests were carried out in the temperature range of 700-1000℃ and strain rate range of 0.05–15 sy1. Experimental results show that the flow stress of Ti-3Al-5V-5Mo alloy decreases with the increase of temperature and the decrease of strain rate. At high strain rate, typically 5 and 15 sy1, discontinuous yielding followed by flow oscillations was observed in both b phase region and aqb phase region; at low strain rate, the flows display single peak stress. The flow stress at a strain of 0.2 was analyzed with a stand constitutive equation. Activation energy parameters were obtained, and they are 133.46kJymol for the b phase region and 661.90kJ/ymol for the α-β phase region. Microstructures of the compressed specimens in water-quenched conditions were critically observed. High temperature deformation mechanisms have been elucidated. In the b phase region, the operative deformation mechanisms are dynamic recovery at high strain rates and grain boundary sliding at low strain rates. In aqb phase region, the α phase undergoes dynamically recrystallization at both high and low stain rates.

Friction plays a significant role in metal-forming operations. To optimize the deformation process, it is necessary to quantify and evaluate the behavior of the lubricants. In this study, the lubrication behavior of A5 glass lubricant was investigated. Ring compression tests were conducted at constant strain rates ranging from 0.05 to 15 s-1 and at temperatures ranging from 750 to 1000℃. At temperatures lower than 950℃, the strain rate has no obvious effect on the friction factor of A5, the most significant parameter being the temperature, an increase in the temperature decreases the friction factorm to reduce. At A5 temperatures above 950℃, the effect of strain rate becomes important, the friction factor m increases with the decrease in the strain rate.

In this paper, clad sheet bonding by cold rolling has been analyzed in depth using the stream function method and the upper bound theorem. Not only have the curvature, the thickness ratio of the rolled product and rolling force, but also the locations of the neutral points and the bond point have been obtained. It is found that at low total thickness reduction, the neutral point on the upper roll contacting the harder sheet usually more closely approaches the entrance of the roll-gap than does neutral point on the lower roll. As the thickness reduction increases, the difference gradually diminishes and even reverses. It is also found that the location of the bond point at the interface is to some extent related to the initial clad ratio. A smaller the clad ratio before rolling may bring the bond point closer to the entrance of the roll-gap, which means a longer bonded length at the interface. Based on this analysis, some means of contributing to the promotion of bond strength are proposed.

The compression test has been used widely in obtailning flow stress data at hot working temperatures, in order to obtain reliable data, Uniform deformation must be ensured by having adequate lubrication tbrougbout testing, in tbis paper, the lubrication bebavior of graphite was investigated by ring compression tests of Ti-6A1-4V alloy at temperatures from 750 to 1000℃ and constant strain rates from 0.05 to 15s 1. it was found that the friction factor m increases with the increase of temperature and with the decrease of strain rate. At temperatures below 800℃, the friction factor m is less than 0.3, so that graphite can be used effectively as a luhiicant in this range of temperatm-e for compression tests.

In the present work, an attempt was made to predict the temperature evolution during the extrusion of 7075 aluminium alloy by means of 3D FEM computer simulation. Results show that ram speed has a significant influence on the temperature distribution in the billet, which continuously changes throughout the process, as a result of complex heat generation and heat loss. The thermal effect results in characteristic variation of extrusion pressure. At a higher ram speed, the decrease of extrusion pressure is faster during the steady-state extrusion, due to more heat generation, less heat loss and thus more steeply decreased flow stress, as the process proceeds. The temperature inhomogeneity on the cross-section of the workpiece entering the die bearing is more pronounced when ram speed is higher. While going through the die, the extrudate undergoes a process of temperature redistribution and the temperature becomes more homogeneously distributed at the die exit. The present simulation does not render support to the general statement that the corner of the extrudate is hotter than the flat surfaces. Incipient melting is predicted to occur after a half of the billet is extruded at a ram speed as low as 1 mm/s corresponding to an extrusion speed of 0.48 m/min, if the billet contains the phases with low melting points. However, if the billet of the same alloy is in an improved metallurgical condition, no melting-related defects would be expected to occur to the extrudate running at a speed eight times faster. The results also confirm the linear relationship between the increase of the maximum temperature and logarithmic ram speed during the steady-state extrusion.