CAJ | 학술논문

用两种不同的热处理制度对稀土和锶综合细化变质的A356合金进行处理,一种是长时间标准处理制度T6(535℃固溶4 h+150℃时效15 h),另一种是短时间的热处理制度ST(550℃固溶2h+170℃时效2 h).采用光学显微镜、扫描电镜及室温拉伸实验等手段分析热处理制度对A356合金微观组织和拉伸力学性能的影响.结果表明:在550℃下固溶2h可以获得Mg、Si过饱和且分布均匀的α(Al)固溶体,并使共晶硅相球化；再经170℃人工时效2h后,可以达到传统T6处理的时效析出效果.拉伸实验结果表明,A356铝合金经传统T6处理得到了最高的拉伸强度和断裂伸长率；通过ST短时热处理后,其拉伸强度、屈服强度及伸长率分别可以达到T6处理时的90％,95％和80％.
용량충불동적열처리제도대희토화송종합세화변질적A356합금진행처리,일충시장시간표준처리제도T6(535℃고용4 h+150℃시효15 h),령일충시단시간적열처리제도ST(550℃고용2h+170℃시효2 h).채용광학현미경、소묘전경급실온랍신실험등수단분석열처리제도대A356합금미관조직화랍신역학성능적영향.결과표명:재550℃하고용2h가이획득Mg、Si과포화차분포균균적α(Al)고용체,병사공정규상구화；재경170℃인공시효2h후,가이체도전통T6처리적시효석출효과.랍신실험결과표명,A356려합금경전통T6처리득도료최고적랍신강도화단렬신장솔；통과ST단시열처리후,기랍신강도、굴복강도급신장솔분별가이체도T6처리시적90％,95％화80％.
Two heat treatments of A356 alloys with combined addition of rare earth and strontium were conducted.T6 treatment is a long time treatment(solution at 535 ℃ for 4 h + aging at 150 ℃ for 15 h).The other treatment is a short time treatment(solution at 550 ℃ for 2 h + aging at 170 ℃ for 2 h).The effects of heat treatment on microstructure and tensile properties of the Al-7％Si-0.3％Mg alloys were investigated by optical microscopy,scanning electronic microscopy and tension test.It is found that a 2 h solution at 550 ℃ is sufficient to make homogenization and saturation of magnesium and silicon in a(Al)phase,spheroid of eutectic Si phase.Followed by solution,a 2 h artificial aging at 170 ℃ is almost enough to produce hardening precipitates.Those samples treated with T6 achieve the maximum tensile strength and fracture elongation.With short time treatment(ST),samples can reach 90％ of the maximum yield strength,95％ of the maximum strength,and 80％ of the maximum elongation.