EFFECT OF EXTRUSION SPEED ON THE MICROSTRUCTURES AND MECHANICAL PROPERTIES OF Ti-6Al-4V ALLOY PREPARED BY COMBINING OF POWDER COMPACT HOT PRESSING AND EXTRUSION UNDER AIR

摘要

Titanium alloys are very promising materials which can be used in the area of aerospace, marine and chemical engineering, biological engineering, etc., due to its advantage of low density, high strength, and excellent corrosion resistance. In this paper, a fast and low-cost method, combining of powder compact hot pressing at 1300℃ under argon atmosphere and hot extruding at 1150℃ in air, with different extrusion speeds (17mm/s, 68mm/s and 122mm/s), was used to prepare Ti-6Al-4V alloy in a short time. It showed that most part of the as-hot-pressed billet (feeding compact) cannot be extruded out when the extrusion speed was 17mm/s, and the length of extrusion rod was 50mm. With increasing of extrusion speed to 68mm/s and 122mm/s, around 2/3 of volume fraction of as-hot-pressed billets were extruded out, and the lengths of the extrusion rods can be reached to 207mm. It had significant influence of extrusion speed on microstructures and properties of as-extruded Ti-6Al-4V alloy rods, and its effects were investigated.