两种含氢钛合金的疲劳断裂特性  

FATIGUE CRACKING CHARACTERISTICS OF TWO HYDROGEN-BEARING TITANIUM ALLOYS

作　　者：何晓[1] 沈保罗[1] 蒋洪俊[2] 

机构地区：[1]四川大学金属材料系,成都610061 [2]成都飞机工业(集团)公司冶金处,成都610092

出　　处：《理化检验（物理分册）》2002年第8期323-327,共5页Physical Testing and Chemical Analysis(Part A:Physical Testing)

摘　　要：对含氢的两种新型钛合金Ti 4Al 2V和Ti 2Al 2 .5Zr拉 拉疲劳断裂特征进行了金相和断口观察。当材料承受大应力疲劳加载时 ,两种钛合金断口形貌除可见到疲劳弧线外 ,与静拉伸断口类似 ,氢含量不同对疲劳断口形貌的影响很小。充氢以后 ,疲劳载荷越低 ,裂纹源越多。不充氢的角裂纹通常以穿晶方式萌生 ,而充氢的角裂纹一般以准解理方式形核。Ti 4Al 2V在裂纹扩展区可见大量清晰的疲劳辉纹 ,而Ti 2Al 2 .5Zr的疲劳辉纹很少 ,且疲劳辉纹的间距比Ti 4Al 2V小得多。面裂纹一般在氢化物位置形核 ,然后穿晶扩展 ,具有沿晶和穿晶混合形貌。氢化物的含量越大 。Metallographic and fractographic observation was made to study the stretching fatigue fracture characteristics of two types of new titanium alloys. Under higher loadings, fatigue fractograph of the two alloys resemble that of static test besides some visible arc lines on fatigue samples, and hydrogen contents contributed little to the mode of fracture. After hydrogen charging, the lower the fatigue loadings were, the more the sources of crack initiation. Edge cracks initiated as transgranular mode for non hydrogen charged samples and as quasi cleavage mode for hydrogen charged ones. Ti 4Al 2V showed more fatigue striations in propagation area than Ti 2Al 2.5Zr, and much bigger gap of striations was observed in the former one. Face cracks normally initiated at hydrides, propagating transgranularly so that mixed fracture modes was seen. The chance of face cracking increased with rise of hydrgen content.

关 键 词：疲劳断裂 钛合金 氢 断口分析 

分 类 号：TG146.23[一般工业技术—材料科学与工程] TG113.25[金属学及工艺—金属材料]