(中南大學(xué) 材料科學(xué)與工程學(xué)院，長沙 410083)
摘 要: 采用常規(guī)力學(xué)性能和疲勞性能測試、掃描電鏡以及透射電鏡觀察等研究T3和T4熱處理制度對含Zr Al-Cu-Mg合金組織和疲勞性能的影響。結(jié)果表明：該合金在T3狀態(tài)下具有更好的綜合性能。預(yù)變形引入高密度位錯導(dǎo)致合金屈服強度顯著提高，而伸長率降低不多。當(dāng)應(yīng)力比為0.5時，T3狀態(tài)合金的S-N曲線位于T4狀態(tài)之上，經(jīng)106循環(huán)周次后，T3狀態(tài)合金的疲勞強度比T4狀態(tài)的高10 MPa。在應(yīng)力強度因子幅度∆K相等的條件下，T3狀態(tài)合金的疲勞裂紋擴展速率比T4狀態(tài)的略慢。
關(guān)鍵字: Al-Cu-Mg合金；S-N曲線；疲勞裂紋擴展速率；疲勞斷口
Al-Cu-Mg alloy containing Zr
（School of Materials Science and Engineering, Central South University, Changsha 410083, China）
Abstract:The effects of T3 and T4 heat treatments on the microstructures and fatigue properties of Al-Cu-Mg alloy containing Zr were studied by tensile and fatigue test, SEM and TEM observations. The results show that the alloy has better combined properties at T3 condition. The high density dislocation introduced by pre-deformation significantly increases yield strength and slightly decreases elongation of the alloy. When the stress ratio is 0.5, with the same level cycles, the fatigue strength at T3 condition is higher than that at T4 condition, such as the fatigue strength (σmax) at 106 cycles is higher 10 MPa than that at T4 condition. Under the same level of stress intensity factor range ∆K, the fatigue crack propagation rate (da/dN) at T3 condition is slower than that at T4 condition.
Key words: Al-Cu-Mg alloy; S-N curve; fatigue crack propagation rate; fatigue fracture
