摘要:
对海绵钛粉、电解钛粉以及氢化脱氢钛粉进行了粉末热挤压的实验研究。观察了挤压材的组织结构并测定了材料的物理机械性能。结果表明,挤压材中多数孔隙由粉末中的夹杂物造成。随加工率增加,材料的孔隙率减小。当挤压比超过一定值时,孔隙率的减小对材料的机械性能影响不大。在高于钛再结晶温度下挤压时,钛材的金相组织呈等轴晶粒形。退火以后,发现材料的晶粒长大,材料的冲击韧性与延性提高。热挤压材的机械性能主要取决于粉末的氧含量,随氧含量的增加,材料强度增高,延性与冲击韧性下降。当粉末的氧含量控制在0.15%以下时,粉末热挤压钛材的性能可达到甚至超过TA1的标准。
Abstract:
The present paper describes the experimental investigations on the hot extrusion of s ponge, electrolytic and HDH titanium powders. The structures were observed and physcial and mechanical properties of extruded materials were determined. The experimental results show that most of the pores in extruded titanium are caused by inclusions in powder The porosity in materials decreases with the increase of extruding reduction ratio.whlile the extruding ratio is up to a given value, the influence of decreasing porosity on the properties of materiais can be neglected. Equiaxed crystal structure was observed when titanium was extruded at above the recrystallization temperature. After annealing coarse grain structure was observed and the impact ductility and the elongation of materials increased. The mechanical properties of titanium depends mainly on the oxygen contens of powder. The strength of material increases with increase of oxyen content, but elongation and impact ductility decrease. The properties of P/M titanium produced by hot extrusion may achieves, or even exceed TAl Standard, if the oxygen content of powder is controlled less than 0.15%.
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