【摘要】 某产品用1420铝锂合金锻件在存放过程中发生开裂。本文通过对失效锻件进行形貌观察以及断口、金相和力学性能分析,结合此锻件的制造工艺,分析认为:此锻件的开裂属于延迟开裂;锻件小端转角区(R区)存在较大的应力,淬火水冷阶段在R区内表面形成微小表层裂纹;长期的存放过程中,锻件表面受到腐蚀,发生应力腐蚀;微裂纹在残余应力及应力腐蚀的作用下缓慢扩展直至发生失稳扩展形成宏观贯穿裂纹,致使锻件开裂。通过车光锻件内外表面及车光后的荧光检查,有效地预防了此类开裂故障的发生。更多还原

【Abstract】 A 1420 aluminum-lithium alloy forging used in a key project cracked when it was deposited in quarry. In this paper,fraction analysis,metallographic analysis and mechanical property analysis were employed to investigate the reason why cracking phenomenon happened. The results indicated that the cracking problem was delayed cracking. Local stress concentration appeared in the R area,where micro-surface cracking formed at the phase of water-cooling. In the process of the long-time storage,the surface of the forging was corroded,resulting in stress occurred. Under the gradual action of residual stress and stress corrosion,micro-crack enlarged to be perforated crack, which resulted in the cracking of the forging. Fortunately,such defect could be prevented by cutting the forging’s internal / external surface away and then detected with fluoroscopy.更多还原