Effects Of Extrusion Ratio Research Articles

Investigation extrusion ratio effect on mechanical behaviour of extruded alloy AA-6063

This article describes effect of extrusion ratio (ER) in direct extrusion process on mechanical behaviours of the alloy 6063 prepared in two different textures as homogenised and rapid quenched (HRQ) and unhomogenised and slow cooled (UHSC) conditions. In the study, AA-6063 alloy was directly extruded as rod by using three different single hole flat type dies with diameters 10, 30 and 50 mm. Forward speed of the main ram of 1600 t extrusion press was kept to be constant when performing of the tests. For suitable pre-heating of the billets, several pre-tests have been performed to keep exit temperatures of the profiles as constant. Six billets from the alloy AA-6063 were prepared as-cast UHSC condition. Another six billets were applied homogenisation and than cooled fast. Billets with two different textures were tested by extruding different ERs and different exit temperatures 510 and 460 °C, respectively. Then the samples from two different textures of the extrusions from the alloy AA-6063 were exposed to both T-1 and T-6 treatments. Consequently, organising various comparable graphics by data from mechanical tests, effects of ER versus to ultimate tensile strength, hardness and elongation percent have been examined.

Effects of hot extrusion parameters on the tensile properties and microstructures of SiC w-2124Al composites

The effects of extrusion ratio and extrusion temperature on tensile strengths and microstructures of 20 vol.% SiC w-2124Al composites were investigated. The alignment of SiC whiskers along the extrusion direction in SiC w-2124Al composites was improved and the aspect ratio of SiC whiskers was decreased with increasing extrusion ratio from 10:1 to 25:1. The SiC w-2124Al composite exhibited the highest tensile strength at the extrusion ratio of 15:1. The aspect ratio of whiskers and the relative density of composite increased with increasing extrusion temperature from 470 °C to 530 °C. The tensile strength of SiC w-2124Al composite increased with increasing extrusion temperature up to 530 °C. Based on the concept of the load transfer efficiency of misoriented SiC whiskers in the 2124Al matrix, the two microstructural parameters of the alignment and aspect ratio of whiskers, which influenced on the tensile strength in an opposite way, were combined into a single parameter proposed as an effective aspect ratio. The highest tensile strength of SiC w-2124Al composite at the extrusion ratio of 15:1 is explained by the largest effective aspect ratio due to the balance of the alignment and aspect ratio of SiC whiskers. A modified phenomenogical equation describing the tensile strength of SiC w-2124Al composites as a function of microstructural parameters was proposed by introducing the effective aspect ratio as a substitute for the average aspect ratio of SiC whiskers.

Influence of extrusion ratio on the thermal properties and morphology of ultradrawn high‐density polyethylene

AbstractSolid‐state extrusion of high‐density polyethylene (HDPE) has received considerable attention. It has been shown that extrudate may have high values of optical clarity, tensile modulus (∼70 GPa = 7 × 1011 dyn/cm2), and c‐axis orientation. The effects of extrusion conditions on the properties of the resultant fibers have, however, not yet been clarified. A systematic study has thus been made here to evaluate extrusion pressure, temperature, and extrusion (draw) ratio, and the molecular weight of extruded HDPE. The effects of extrusion ratio on the degree of crystallinity, melting behavior, crystal orientation, and dimensional change along the extrusion direction are reported.