Redistribution of alloy elements in aging of austenitic chrome-manganese steel containing nitrogen

Conclusions In interrupted decomposition of the austenite of chrome-manganese steel containing nitrogen in the 600–900°C range the alloy element content in the nitride phase formed changes. The quantity of chromium increases while that of iron decreases significantly. The manganese content in the nitride is low and remains approximately constant.The residual austenite in the grains which have undergone interrupted decomposition is gradually depleted of chromium and nitrogen.The growth of pearlitelike colonies consisting of transformed austenite and type M₂N nitride is controlled simultaneously by the mechanisms of grain-boundary and three-dimensional diffusion.Institute of Metallurgy and Metals Technology, Sofiya, Peoples Republic of Bulgaria. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 11, pp. 60–61, November, 1988.     

Heat treatment of cast alloy AK18 pistons

Conclusion The life of alloy AK18 pistons, governed in particular by hardness, may be increased as a result of reducing the casting temperature, increasing the cooling rate after alloy solidification, correcting alloy composition within the grade limits, and using homogenizing before artificial aging.Kostroma Agricultural Institute. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 6, pp. 28–30, June, 1987.     

热处理对含Hf钛铝基合金显微组织的影响

研究了双温热处理工艺对含铪Ti-Al基合金组织的影响规律。差热分析法(DTA)测定结果显示,合金的共析反应温度Te=1110℃,α相转变温度Tα=1330℃。用金相法获得了优化的双温热处理工艺为:1400℃×1 h→50℃水冷,1280℃×3 h→空冷。     

Evolution of intermetallic phases of Al-Zn-Mg-Cu alloy during heat treatment

Al-Zn-Mg-Cu alloy is a favorable choice for aerospace applications requiring good combination of strength and toughness, which is greatly influenced by the coarse intermetallic particles. The evolution of intermetallic particles in an Al-Zn-Mg-Cu alloy during heat treatment was studied by field emission gun scanning electron microscopy （FEG-SEM） and X-ray diffractometry（XRD）. The results show that there are lamellar eutectic structure （α（Al）＋Mg（Zn,Al,Cu）：） and Al7Cu：Fe particles in the solidified structure. The Al7Cu2Fe particles are embedded in the eutectic structure. The content of eutectic structure decreases with the increase of holding time and disappears after 24 h. The size and morphology of Al7Cu：Fe particles exhibit no change during the heat treatment. It is found that the AI：CuMg phase is formed during the treatment at 460 ℃. A transformation process from the primary eutectic phase Mg（Zn,Al,Cu）2 to Al2CuMg is observed, and the transformation mechanism and kinetics are analyzed, The AI：CuMg constituents form in the primary Mg（Zn,Al,Cu）： phase, and grow along the eutectic microstructure.     

热处理对含Si蒙乃尔合金组织及硬度的影响

研究了热处理工艺对含Si蒙乃尔合金组织及硬度的影响。结果表明:固溶温度在820～1120℃之间,合金随着固溶温度的升高,晶界处的β-Ni3Si相的数量明显减少;当固溶温度达到1020℃时,晶界处β-Ni3Si相完全溶解;随着固溶温度的进一步升高,当温度达到1120℃时,晶界因熔化而出现了鱼骨状过烧组织。时效温度在500～700℃之间,合金随着时效温度的升高,合金中的β-Ni3Si强化相的数量逐渐增加,硬度也随之增大;在时效温度为600℃时,β-Ni3Si强化相析出的数量最多,合金硬度最高;时效温度为700℃时,合金中的部分β-Ni3Si相聚集长大,合金硬度降低。     

7A33铝合金薄板热处理工艺研究

试验研究了退火、淬火、双级时效工艺参数对7A33铝合金薄板力学性能和组织的影响;测定了该合金试样的晶间腐蚀性能、应力腐蚀性能和电导率;确定了能使该合金薄板获得较好综合性能的O状态退火工艺制度为390℃~410℃、保温2 h;T62状态热处理工艺制度为淬火温度460℃、水淬,双级时效制度75℃1 h+150℃20 h。工业化生产出了符合要求的7A33铝合金薄板。     

Grain refinement in a cast high Nb containing TiAl alloy by heat treatment

The grain refmement of an as-cast Ti-46Al-8.5Nb-0.2W (atom fraction in %) alloy by the cyclic heat treatments was studied. The heat treatment scheme included a tempering at 1250℃ and cyclic tempering at 1000 and 1200℃ three times after solution treatment at the temperature above α phase transus followed by immediate fan cooling. The fine and homogeneous near-γ microstructure can be obtained by this heat treatment, which causes the breakdown of as-cast microstructure and prevents the anomalous growing of originalγ phase.     

Cu-Cr-Fe-Ni合金形变热处理过程中的组织与性能

采用非真空熔炼并经热轧—固溶—冷轧—时效热处理工艺制备Cu-0.59Cr-0.078Fe-0.081Ni合金板,探究热处理和冷变形对合金显微组织、电导率和硬度的影响。结果表明:Cu-Cr-Fe-Ni合金大气熔铸后呈明显的枝状晶组织,经固溶处理后合金发生再结晶,硬度和电导率都相应的降低,分别为65.9 HV0.2、41.7%IACS;经过冷变形处理后合金的硬度显著提高,变形量达90%时,合金的硬度高达144.7 HV0.2;合金变形后在450 ℃时效的过程中硬度先增加后减少,变形量为60%时,时效30 min达到峰时效,此时硬度、电导率分别为155.5 HV0.2、71.4 %IACS。     

Quenching of the AK4 alloy

Conclusions The optimum quenching conditions, for AK4 steel are heating at 535°C and quenching in hot water.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 7, p. 32, July, 1963     

Structural evolution of ZA27 alloy during semi-solid isothermal heat treatment

1　ＩＮＴＲＯＤＵＣＴＩＯＮＳｅｍｉ ｓｏｌｉｄｆｏｒｍｉｎｇｈａｓａｗｉｄｅｕｓｅｆｏｒｉｔｓｉｍｐｒｏｖ ｉｎｇｐｒｏｄｕｃｔｑｕａｌｉｔｙａｎｄｄｅｃｒｅａｓｉｎｇｃｏｓｔｓ[1～ 3] .Ｉｔｉｓｃｏｍｐｏｓｅｄｏｆｔｈｒｅｅｍａｉｎｐｒｏｃｅｓｓｅｓ ,ｓｕｃｈａｓｓｅｍｉ ｓｏｌｉｄｍａｔｅｒｉａｌｐｒｏｄｕｃｔｉｏｎ ,ｐａｒｔｉａｌｒｅｍｅｌｔｉｎｇａｎｄｔｈｉｘｏｆｏｒｍ ｉｎｇ .Ａｍｏｎｇｔｈｏｓｅ ,ｔｈｅｓｅｍｉ ｓｏｌｉｄｂｉｌｌｅｔｐｒｏｄｕｃｔｉｏｎｉｓｔｈｅｍｏｓｔｉｍｐｏｒｔａｎ…     

含Sc超高强Al-Zn-Mg-Cu-Zr合金的回归再时效处理制度

采用透射电镜分析、力学拉伸性能测试和电导率测试, 研究不同回归再时效(RRA)处理制度对含Sc超高强Al-Zn-Mg-Cu-Zr合金组织与性能的影响.结果表明:采用120 ℃,24 h预时效+180 ℃,30 min回归处理+120 ℃,24 h终时效的RRA处理工艺,可以使合金获得理想的力学性能和抗应力腐蚀性能;与T6态相比,该工艺获得的合金强度仅略微下降,而电导率则大大提高;含Sc超高强Al-Zn-Mg-Cu-Zr合金经RRA处理后,晶内含大量均匀细小的η'相和少量的η平衡相,合金晶界处的平衡相粗化明显,呈现断续、孤立分布;与T6态处理的合金相比,无沉淀析出带变宽;其晶内析出相与T6峰值时效态的类似,晶界组织与双级过时效态的组织类似.     

7A04铝合金T6处理开裂失效分析

<正>批量生产某铝合金件时,在固溶时效后的超声波探伤时,发现部分工件出现明显的宏观裂纹,影响了稳定生产,造成了较大的经济损失,为防止此类质量事故的再次发生,对该产品的铝合金件的失效原因进行分析。1失效铝合金件的基本情况失效铝合金件材料为7A04,由120 mm棒料经热模锻成型而成,后续经T6处理和机械加工。同一批     

含钪7xxx系铝合金的再结晶

采用金相显微镜和透射电子显微镜研究了含钪Al-Zn-Mg-Cu-Zr系铝合金组织的再结晶,测试了不同温度下退火1h合金的硬度。结果表明:含0.20%Sc的7xxx系铝合金(冷变形量50%)的再结晶起始温度为475℃,再结晶终了温度为525℃。合金在均匀化以及热加工过程中析出细小、弥散的二次A l3(Sc,Zr)粒子钉扎位错、亚晶界和晶界,使回复过程中的位错运动受阻,保持基体内较高的位错的密度,阻碍加热时位错重新排列呈亚晶界以及更进一步发展成大角度晶界的过程;阻碍了再结晶核心长大过程,阻碍大角度晶界的迁移,从而提高再结晶温度。     

热处理工艺对含Er压铸Al-Si-Mg合金组织及性能的影响

以含Er的压铸Al-Si-Mg合金为研究对象,通过拉伸性能测试、光学显微镜(OM)、扫描电镜(SEM)、能谱(EDS)及透射电镜(TEM)分析及定量统计,分析研究了不同固溶、时效工艺对合金组织及性能的影响。结果表明:双级固溶有利于一次相回溶至基体,使合金的塑性提高;固溶温度、时间的提高能够增加固溶到基体中的溶质原子和一次相的数量。Al-Si-Mg合金峰时效时,主要的强化相为β″、β′相,β′相主要表现为长条状及“T”字形。当热处理工艺为(280 ℃×3 h+530 ℃×3 h)固溶+170 ℃×3 h时效时,合金的伸长率达8.5%,具有高塑性; 热处理工艺为(280 ℃×3 h+540 ℃×10 h)固溶+170 ℃×10 h时效时,合金的抗拉强度为344 MPa,屈服强度为312 MPa,合金具有高强度。