时效制度对B95_(ЛЧ)锻件断裂韧性和抗应力腐蚀性能的影响

Influence of Ageing on Fracture Toughness and Stress Corrosion Cracking Resistance of B95_(ЛЧ)Forging

研究了双级时效工艺和回归再时效(RRA)工艺对B95ЛЧ铝合金锻件的断裂韧性和应力腐蚀性能的影响。测定了9种双级时效工艺和3种RRA工艺状态下的断裂韧度,同时测定了各时效工艺状态下的电导率和强度指标。通过对试样组织性能的分析研究发现:当一级时效条件相同时,随着二级时效温度的升高和时效时间的延长,断裂韧度和抗应力腐蚀性能提高,其中以115℃×7h+185℃×13h为最佳时效工艺。RRA工艺能使合金获得最高的强度,经回归20min的RRA试样的抗应力腐蚀性能也能达到115℃×7h+185℃×13h的水平,但断裂韧度不如采用较高二级时效温度的试样。

The effect of two-stage ageing and retrograssion and reaging heat treatment（RRA）on the fracture toughness and stress corrosion cracking resistance of B95ЛЧ forging was studied. The fracture toughness ,conductivity and strength under nine kinds of two-stage ageing treatment and three kinds of RRA treatment were measured. The results showed that the microstructure and property of the fracture toughness and stress corrosion cracking resistance increased with increase of ageing time and ageing temperature, when the condition of first order ageing treatment was identical. Of all two- step ageing treatment （115 ℃ × 7h＋185 ℃× 13h） was the best ageing one. Although RRA treatment could make B95ЛЧ forging the highest strength and stress corrosion cracking resistance, which can reach the level of the treatment （115 ℃× 7 h ＋ 185 ℃× 13 h ） after twenty minutes of regression as well, the fracture toughness was lower.