(中南大學(xué) 材料科學(xué)與工程學(xué)院，長沙 410083)
摘 要: 采用光學(xué)金相、示差掃描量熱分析、掃描電鏡、室溫拉伸及斷裂韌性實(shí)驗(yàn)，研究多級(jí)固溶處理對(duì)7050鋁合金強(qiáng)度和斷裂韌性的影響。結(jié)果表明：7050鋁合金厚板經(jīng)多級(jí)強(qiáng)化固溶后，隨最后一級(jí)溫度的增加，可溶性粗大第二相減少，其強(qiáng)度和斷裂韌性增加，當(dāng)最后一級(jí)溫度為493 ℃時(shí)，合金的斷裂韌性和強(qiáng)度達(dá)到峰值，其斷裂韌性(KIC)、屈服強(qiáng)度(σ0.2)和抗拉強(qiáng)度(σb)分別為37.4 MPa·m1/2、500.6 MPa和534.0 MPa；當(dāng)最后一級(jí)溫度超過493 ℃時(shí)，由于再結(jié)晶分?jǐn)?shù)急劇增加、晶粒快速長大，斷裂韌性和強(qiáng)度又逐漸降低；當(dāng)多級(jí)固溶最后一級(jí)的溫度和時(shí)間與單級(jí)固溶一致時(shí)，經(jīng)多級(jí)強(qiáng)化固溶后的7050鋁合金具有比單級(jí)固溶時(shí)更高的斷裂韌性和強(qiáng)度。
關(guān)鍵字: 7050鋁合金厚板；斷裂韌性；固溶處理；拉伸性能
（School of Materials Science and Engineering, Central South University, Changsha 410083, China）
Abstract:The effects of the multi-stage promotively-solutionizing treatment on the tensile property and fracture toughness of the 7050 aluminum alloy plate were investigated by optical microscopy (OM), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), tensile test and toughness test. The results show that the tensile property and fracture toughness of the multi-stage promotively-solutionizing treated samples increase when the last stage temperature increases. When the last stage temperature is 493 ℃，the tensile property and fracture toughness of the multi-stage promotively-solutionizing treated samples reach the peak, the fracture toughness (KIC), yield strength (σ0.2) and ultimate tensile strength (σb) are 37.4 MPa·m1/2, 500.6 MPa and 534.0 MPa respectively. Then, the tensile property and fracture toughness of the multi-stage promotively-solutionizing treated samples decrease with the increases of the last stage temperature, because the grains grow very fast. The tensile property and fracture toughness of the multi-stage promotively-solutionizing treated samples are better than that of the single-stage solution treated samples.
Key words: 7050 aluminum alloy; fracture toughness; solution treatment; tensile property
