大尺寸喷射沉积耐热铝合金管坯楔压致密化与力学性能  

Densification and mechanical properties of spray deposited large scale heat-resistant aluminum alloy tubular preforms during wedge pressing

作　　者：陈振华[1] 陈志钢[1] 陈鼎[1] 贺毅强[1] 陈刚[1] 

机构地区：[1]湖南大学材料科学与工程学院,长沙410082

出　　处：《中国有色金属学报》2008年第8期1383-1388,共6页The Chinese Journal of Nonferrous Metals

基　　金：国家自然科学基金资助项目(50304008)

摘　　要：基于多道次局部小变形累积致整体成型的工艺思路,采用一种新型的楔形压制工艺,对大尺寸Al-Fe-V-Si耐热铝合金喷射沉积管坯进行有效致密化,压制出尺寸为douter330mm×dinner314mm×78mm及douter330mm×dinner312mm×113mm的力学性能良好、整体均匀致密、外形圆整的耐热铝合金管材,并对楔形压制的致密化规律及其合金的组织与性能进行研究。结果表明:不锈钢包套在楔形压制过程中可以适当增大静水压力,并改善管坯的温度均匀性,使管坯中的孔洞显著锻合,材料的有效承载面积增加,沉积坯中的弱界面和层状组织得到有效改善,从而使其成形性能得以提高;当楔形压制的变形程度为50.4%时,管坯的力学性能及相对密度由沉积态的σb=125MPa,δ=15%,82%分别提高到301MPa,9.3%及99.3%。该工艺适合于加工大尺寸多孔金属管坯,具有经济、实用的优点及较好的工业应用前景。A new wedge pressing process for compressing large scale porous tubular preforms was adopted based on the idea of accumulating local small deformation as to integral forming. Heat-resistant aluminum alloy tubes of douter 330 mm × dinner 314 mm × 78 mm and douter 330 mm × dinner 312 mm × 113 mm with well mechanical properties, density and good contour were fabricated. Densification behavior, microstructure and mechanical properties of the spray deposited Al-Fe-V-Si tubes during wedge pressing were investigated. The results show that, with increasing hydrostatic pressure and uniformly distributed temperature, the fragile interfaces and lamellar structure in the as-deposited materials are effectively improved, pores are closed and the mechanical properties are substantially upgraded due to increasing effective loading area after the stainless steel package wedge pressing. The mechanical properties and relative density of the deposits increase from 125 MPa, 0.15% and 82% to 301 MPa, 9.3% and 99.3% respectively after the reduction of 50.4%, indicating that the novel method is feasible, practical and cost-effective.

关 键 词：耐热铝合金 多层喷射沉积 管坯 楔形压制 致密化 力学性能 

分 类 号：TG146.2[一般工业技术—材料科学与工程]