镍基耐蚀合金GH536B(G3)的高温变形特性

通过Thermomacmaster-Z热模拟机试验和显微组织观察,研究了镍基耐蚀合金GH536B(G3,%:0.002C、20.30Cr、17.50Fe、8.70Mo、1.32W、1.90Cu、0.20Nb)1 030～1 300℃、应变速率1～25 s-1的应力-应变曲线以及温度对合金断面收缩率的影响,高温变形下合金组织的变化和应变速率对合金动态再结晶温度的影响.结果表明,G3合金变形抗力大,热成形温度区间小,随应变速率增大,热塑性降低;Φ中10 mm×140 mm试样拉伸速率为100 mm·s-1,合适的成形温度为1 130～1 260℃,当拉伸速率为200 mm·s-1,合适的成形温度为1 130～1 220℃.     

新型喷射成形镍基高温合金热变形行为的研究

采用Gleeble-3500热模拟实验机对新型喷射成形镍基高温合金在1050~1140℃,应变速率为0.01~10.0 s-1,最大工程应变量为80%的条件下,进行了等温恒应变轴向压缩热变形实验。确定了该合金最佳热变形条件为温度1050℃,应变速率10.0 s-1,工程应变量20%~60%;分析了变形条件对流变应力、峰值应力及软化系数的影响规律,在相同的应变速率下,随着温度的升高,峰值应力降低;在相同的实验温度下,随着应变速率的升高,峰值应力降低;软化系数增加。计算了该喷射成形合金的热变形激活能为920.74 kJ.mol-1,从而确定了该合金的本构方程,经验算此方程较好地描述该合金的变形特点。     

7055铝合金的热变形行为及挤压工艺研究

采用Gleeble热模拟压缩试验研究了7055铝合金的热变形行为和组织演变规律,获得了变形温度和应变速率理论参数,实现了工业生产验证。结果表明:当温度在380～460℃范围内,应变速率在0.001～0.1s-1间时,合金表现为稳态流变;应变速率为1s-1时,合金发生流变硬化;在此变形参数区间的组织演变以动态回复为主。当变形温度为460℃、应变速率为10s-1时,合金发生严重的塑性失稳。基于热模拟试验与组织分析提出了热变形工艺理论参数,并在工厂进行了挤压验证,最终确定了7055合金较佳的挤压温度为420～440℃,挤压速率为0.3～0.7 m/min。     

ODS-310合金的热变形行为及热加工图

采用Gleeble-1500D热模拟试验机研究机械合金化制备的ODS-310合金在变形温度为1 050~1 150℃、应变速率为0.001~1 s-1条件下的高温变形行为,测定其真应力-应变曲线,分析其流变应力与应变速率及变形温度三者之间的关系,并采用Zener-Hollomon参数法建立ODS-310合金的高温变形本构方程,基于动态材料模型,构造ODS-310合金的热加工图。结果表明:ODS-310合金的流变应力随变形温度降低或应变速率提高而增大;该合金热变形过程中的流变行为可用双曲线正弦模型来描述,在实验条件下的平均变形激活能为828.384 kJ/mol;真应变为0.4的热加工图表明,ODS-310合金在高温变形时存在2个加工失稳区,即变形温度为1 050~1 070℃、变形速率为0.01~1s-1的区域,和变形温度为1 130~1 150℃、变形速率为0.1~1 s-1的区域;ODS-310合金的最佳变形温度和应变速率分别为1 150℃和0.001 s-1。     

粉末冶金TiAl合金热变形行为及加工图的研究

采用热模拟压缩试验研究了粉末冶金TiAl合金在温度1000～1150℃、应变速率0.001～1s-1范围内的高温变形特性,发现合金的流动应力-应变曲线具有应力峰和流变软化特性。为了研究TiAl合金在有限应变下的变形行为,基于动态材料模型(DMM)建立起了TiAl合金加工图。试验结果表明,在高应变速率(0.1s-1)变形时,材料落入流动失稳区域,出现表面开裂。这对材料的变形是有害的,要避免在流动失稳区进行热加工处理。而在温度为1000～1050℃,应变速率为0.001～0.01s-1时,功率耗散率η值在35%～50%之间。这个区域对应的变形机制为动态再结晶,适合进行热加工。在高温(≥1100℃),低应变速率(0.001s-1)变形时,功率耗散率η达到最大值60%,此时材料发生超塑性变形。     

15Cr-30Ni-Fe基气阀合金的热变形行为研究

采用热模拟试验机对15Cr-30Ni-Fe基气阀合金试样在变形温度为900~1 050℃、应变速率为1~20 s-1内进行单道次热压缩变形试验,研究该合金的高温变形行为。试验结果表明,该合金为热敏感性和应变速率敏感型材料。15Cr-30Ni-Fe基气阀合金热加工图表明,该合金存在两个典型的动态再结晶区域,一个温度范围为1 030~1 050℃,应变速率为4~20 s-1,对应的峰值效率为25%;另一个温度范围为970~1 020℃,应变速率为8~20 s-1,对应的峰值效率为24%。     

700MPa微合金高强钢奥氏体高温变形行为研究

研究了一种700 MPa微合金高强钢。在热力模拟试验机上进行了试验钢的单道次压缩试验,通过其各种变形参数的研究,建立了试验钢的变形抗力数学模型和动态再结晶模型。试验结果显示:试验钢在变形温度为950℃,应变速率为0.1 s-1;变形温度为1 000℃,应变速率为0.1 s-1;变形温度为1 050℃,应变速率为0.1s-1或1 s-1;变形温度为1 100℃,应变速率为0.1 s-1、1 s-1或5 s-1这几种条件下会发生动态再结晶。     

FGH4102粉末高温合金等温热模拟压缩试验及动态再结晶组织研究

本文研究了新型第四代粉末高温合金FGH4102在等温热模拟压缩过程中的组织演变,对γ′相在动态再结晶过程中的作用进行了探讨。结果表明,热等静压态合金在1 060～1 120℃温度范围变形时,热加工性能较好。1 140℃变形后试样容易发生开裂,合金热加工性能较差。合金在γ+γ′两相区变形时均发生了不同程度的动态再结晶,再结晶晶粒尺寸远小于热等静压态的晶粒尺寸。变形过程中,尺寸较大的γ′相起到促进动态再结晶的作用。变形参数对动态再结晶的影响非常显著。低温高应变速率变形时,γ′相促进动态再结晶形核占主导地位,再结晶晶粒比较细小;高温低应变速率变形时,晶粒长大逐渐占据主导地位,再结晶晶粒尺寸较大。     

Ti-25Al-14Nb-2Mo-1Fe合金热压缩变形流变应力行为与微观组织演变的研究

在Gleeble-3500热模拟试验机上对Ti-25Al-14Nb-2Mo-1Fe合金进行了等温恒应变速率压缩试验,研究了在变形温度为950~1 100℃,应变速率为0.001~1 s-1,最大变形程度为50%的条件下合金的热压缩变形流变应力行为与微观组织演变。结果表明:Ti-25Al-14Nb-2Mo-1Fe合金的流变应力对变形温度和应变速率均较为敏感,其流变应力曲线具有应力峰值、流变软化和稳态流变的特征。在变形温度为950℃,应变速率为0.001~0.1 s-1的条件下,Ti-25Al-14Nb-2Mo-1Fe合金的热变形特性为片层组织球化,其热变形机制可用晶界分离球化模型进行解释说明;在变形温度为1 000~1 100℃,应变速率为1 s-1的条件下,材料只发生了动态回复现象;在变形温度为1 050~1 100℃,应变速率为0.001~0.1 s-1的条件下,材料发生了动态再结晶现象。     

镍基粉末高温合金热变形特性的研究

针对一种镍基粉末高温合金进行了热变形特性的研究.研究结果表明,该合金的最佳变形温度区间为1050～1175℃,最大允许变形量为40%.当变形温度t=1125℃、应变速率ε=101s-1或ε=100 s-1时,热变形后该合金的平均晶粒度为10级.     

China's Major Non-ferrous Metals Imports & Exports

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Zinc Production by Province in 2014

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80% of Chinese Firms Purchasing Overseas Mines Ended up in the Red

<正>Minmetals Resources acquired the world’s largest copper mine under construction for USD5.85 billion.One after another,listed companies Jien Nickle,China Molybdenum and Chihong Zinc and Germanium raised money to get involved in overseas mining projects…SOEs and private enterprises are engaged in a frenzy of overseas mine purchasing.A reporter with Economic     

Copper Processing Profit Dropped Sharply,Copper Consumption Will Face Impact in the Second Half of the Year

正Judging from China’s copper consumption field,the biggest consumption unit is electric power,which accounts for 47%of total consumption;it is followed by light industry sector,including household electrical appliance,machinery,durable goods and hardware etc,which accounts for 22%of total consumption;followed by transportation field,     

Central Geological Prospecting Fund Newly Added 16.47 Million Tonnes of Bauxite in 2013

正In 2013,the Central Geological Prospecting Fund(CGPF)Project newly discovered 15 ore fields,including 3 large above ore fields,and 5medium sized ore fields.The reporter learned from the recently published"Annual Report of Central Geological Prospecting Fund Project(2013)"that,from 2006 to 2013 the CGPF     

Manufacturers of Copper Tube for Central Air Conditioner Use Face Mounting Pressure in the Final Quarter of the Year

正This year,the investment growth rate of real estate industry continued to slow down,sold area of commercial housing also dropped significantly,which brought huge pressure to the domestic air conditioning manufactures.In the first half of the year,by relying on high growth in national financial expenditure,along with investment in public infrastructure     

Xinjiang Ranks No.1 in Production of Primary Aluminum in China

正Kang Yi,Honorary Chairman of China Nonferrous Metals Industry Association,said recently at the Forum on Development of the Non-ferrous Metals Industry in Central and Western China held in Zhengzhou that,as more and more electrolytic aluminum factories in Xinjiang came into operation,the electrolytic aluminum output of Xinjiang had reached2,275,000 tons in the first 7 months this year,     

Shenhuo Coal Industry and Electricity Power Completed800,000 t/a Aluminum Project in Xinjiang

正"Xinjiang project has been completed according to schedule,but total completion and total start of production are two different concepts,after completion it still needs a gradual process of reaching production target."On the morning of November 3,Shenhuo Coal Industry and Electricity Power told investors the above statement on the investor interaction platform.     

Guangdong Metal Transaction Center has Become the Second Largest Precious Metal Transaction Platform Nationwide

正The reporter learned from Guangdong Province Precious Metal Transaction Center that in 2013the Center maintained healthy development momentum,and had become the second largest precious metal transaction platform in China in terms of market size;currently Guangdong is quickening steps of financial innovation for the Center,aiming to build a transaction center with international core competitiveness.     

Seven Rare Earth Projects Involving Close to 3 Billion Yuan Investment Landed In the HighTech Zone

正On May 22,Baotou Rare Earth Industry Cooperation Consultation MeetingProject Agreement-signing Ceremony was held in Ningbo,nearly 40 enterprises from Ningbo,Guangdong,Hunan,and Shanxi participated in project consultation.After multi-lateral communication,agreements were signed for a total of 7 rare earth projects successfully.