Ti—10V—2Fe—3Al合金的热变形行为

本文测试了Ti-10V-2Fe-3Al合金在700～950℃温度范围内,5×10~(-3)s~(-1)～10s~(-1)七个应变速率下的真应力-应变(σε)曲线,分析了变形组织,并对β区动态再结晶的形核机制进行了探讨。结果表明,在β区850～950℃下,应变速率ε=1s~(-1)～10s~(-1)范围内变形时,动态回复是主要软化机制,经计算得:应力指数n=4.1,激活能Q=195kJ/mol;当 ε≤10~(-1)s~(-1)时,有动态回复和动态再结晶两种软化机制,此时n=3.9,Q=157kJ/mol。α+β区变形时,有动态回复和动态再结晶两种软化机制。     

9Cr-2W耐热合金高温变形机制研究

对9Cr-2W耐热合金进行了热变形温度900～1300℃和应变速率0.005～5.000 s-1条件下热压缩模拟实验,分析该合金热变形应力应变曲线、热变形组织演变,并测试1150和1300℃下的热变形织构。结果表明,9Cr-2W耐热合金热变形软化方式主要与温度有关,在应变速率0.500 s-1时,900～1050℃出现明显加工硬化,为动态回复型;1100～1200℃动态再结晶新晶粒沿原晶界分布,为不连续动态再结晶型;1250～1300℃沿原晶界出现锯齿形,为几何动态再结晶型。同时,应变速率对热变形软化方式也有一定的影响,随着应变速率的提高,发生不连续动态再结晶温度范围变宽,细化晶粒效果明显。结合9Cr-2W耐热合金变形织构特征,1150℃热变形组织以动态回复为主,织构相对集中,晶粒择优取向强一些;而1300℃热变形组织基本为等轴晶粒,发生了完全动态再结晶,相对应织构漫散,择优取向相对弱一些。     

Cu-Cr-Zr合金的热变形行为

采用Gleeble-3500热模拟实验机对Cu-Cr-Zr合金进行了压缩变形实验,分析了在变形温度为25~700℃、应变速率为0.0001~0.1000s-1的条件下流变应力的变化规律,利用扫描电镜及透射电镜分析合金在热压缩过程中的组织演变及动态再结晶机制。结果表明:Cu-Cr-Zr合金在热变形过程中发生了动态再结晶,且变形温度和应变速率均对流变应力有显著的影响,流变应力随着变形温度的升高而降低,随着应变速率的增加而升高,说明该合金属于正应变速率敏感材料;当变形温度为400~500℃时,低应变速率(0.0001~0.0010 s-1)的真应力-真应变曲线呈现动态再结晶曲线特征,高应变速率(0.01~0.10 s-1)的真应力-真应变曲线呈现动态回复特征;在真应力-真应变曲线的基础上,采用双曲正弦模型能较好地描述Cu-Cr-Zr合金高温变形时的流变行为,建立了完整描述合金热变形过程中流变应力与应变速率和变形温度关系的本构方程,确定了合金的变形激活能为311.43 kJ·mol-1。     

变形温度对TC11合金低应变速率下的变形行为及组织的影响

采用THERMECMASTOR-Z热模拟试验机研究了TC11钛合金在变形温度780～1080℃,应变速率0.001～1 s-1范围的热变形行为,并采用金相显微镜研究了变形温度对TC11钛合金组织的影响,主要研究结果如下:变形温度对TC11钛合金的流动应力有显著影响,在较高温度或较低应变速率时,变形呈稳态流动特征;在较低温度或较高应变速率时,变形呈流变软化特征.在β单相区,当应变速率为1 s-1时,组织主要为拉长的β晶粒和少量的动态再结晶晶粒;当应变速率为O.01～0.1 s-1时,变形机制主要为动态再结晶;当应变速率在0.001 s-1附近时,变形机制为动态回复.在(α+β)两相区,变形温度870～960℃,应变速率0.001 s-1附近时,变形机制为超塑性.     

7N01铝合金热压缩流变行为研究

采用Gleeble-1500D热模拟机进行热压缩变性试验,研究7N01铝合金在变形温度为340 ～460℃、应变速率为0.01～ 10.00 s-1条件下的流变应力行为.结果表明:变形温度和应变速率对合金流变应力有显著影响,流变应力随变形温度的升高而降低,随应变速率的增加而升高;合金在低应变速率(0.01,0.10,1.00s-1)时主要为动态回复软化机制,而在高应变速率(10.00 s-1)时出现动态再结晶软化;7N01铝合金的高温流变行为可用Zener-Hollomon参数描述.     

基于摩擦修正的TB8合金热压缩流变应力行为分析

采用Gieeble-1500热模拟试验机对TB8(Ti-15Mo-2.7Nb-3Al-0.2Si)合金进行了等温热压缩变形试验,温度范围为750-1100℃,应变速率范围为0.01～1s-1.在热压缩过程中由于摩擦影响导致流变应力不能真实反映材料的高温变形行为.采取一种简便的方法对实验数据进行了摩擦修正,研究了TBS合金热变形流变应力行为,并对合金的变形机制进行了初步探讨.结果表明:热压缩过程中摩擦对于流动应力的影响十分显著,采取的修正方法降低了实验中摩擦引起的误差;TB8合金的热变形行为具有高度的变形温度和应变速率敏感性,随着变形温度的提高和应变速率的降低,真应力显著降低;动态回复和动态再结晶是TB8高温变形时主要软化机制.     

40Cr钢热变形行为研究

利用Gleeble-3500热模拟试验机在变形温度900～1 200℃和应变速率0.01～10 s^-1范围内，对40Cr钢试样进行压缩实验。研究了40Cr钢真应力-应变曲线特征，建立了峰值应力、应变速率和变形温度间的本构方程，并确定了40Cr钢热变形激活能为310.625 kJ/mol。研究结果显示：40Cr钢热变形时的流变软化机制为动态回复和动态再结晶；随着变形温度增加和应变速率减小，流变应力减小；试样的变形温度越高，应变速率越低，显微组织中的动态再结晶越完全，并且动态再结晶晶粒越容易长大。     

Cu-Cr-Zr-Ce合金高温流变应力的研究

利用Gleeble-1500D热模拟试验机对Cu-Cr-Zr-Ce合金在变形温度为600～800℃、应变速率为0.01～5 S-1条件下进行了热压缩试验,测定了其应力-应变曲线,并通过光学显微镜观察了其热压缩过程中的微观组织.结合两者分析了动态回复和再结晶机制.结果表明,动态再结晶是该合金软化的主要机制.     

工业纯铝的动态再结晶行为

文章研究工业纯铝在等温压缩过程中流变应力特征和微观组织的演变。结果表明：在同一应变速率0．01／s下，变形温度为220℃和300℃时，真应力-真应变曲线呈稳态特征，材料只发生了动态回复，当T≥380℃时，发生了动态再结晶；任同一变形温度460℃，不同应变速率（1／s，0．1／s，0．01／s，0．001／s）下变形时发生了动态再结晶；动态再结晶机制是连续动态再结晶和几何动态再结晶，其真应力-真应变曲线呈单峰特征？     

生物医用Ti-6Al-7Nb合金高温变形行为研究

为了研究用于外科植入生物材料Ti-6Al-7Nb合金的热变形行为,利用Gleeble 2000热模拟实验机对Ti-6Al-7Nb合金在750～900℃温度范围和0.001～10.000 s-1应变速率范围内进行等温热压缩实验,试验在氩气保护下进行,采用金相显微镜和透射电镜观察热变形后的组织;通过计算变形激活能分析Ti-6Al-7Nb合金在热压缩过程中的变形机制。结果表明:流变应力在经历加工硬化阶段后均表现出流变软化现象,在较低应变速率ε=0.001～0.100 s-1时,材料的软化主要受α相动态再结晶影响;而在较高应变速率ε=1～10 s-1时,材料基本不发生再结晶,其软化是由于钛合金在变形过程中的绝热效应造成的。通过Arrhenius方程计算出合金在750,800,850和900℃下的变形激活能分别为209.25,196.01,194.01和130.40 kJ.mol-1;在750～850℃下的激活能接近于α-Ti的自扩散激活能(200 kJ.mol-1),表明在750～850℃的变形由α-Ti自扩散参与的动态再结晶控制;在900℃下激活能略低于β-Ti的自扩散激活能(160 kJ.mol-1),说明在900℃下的变形机制由β相的动态回复控制。综合考虑变形行为与组织细化因素,温度在750～850℃,变形速率在0.01～0.10 s-1范围为良性热加工区域。     

Chinalco Signed Framework Agreement for Strategic Cooperation with Harbin Municipal Government

正Last month,Chinalco signed framework agreement for strategic cooperation with Harbin Municipal Government in Harbin Xiong Weiping,Chairman of Chinalco,said that based on the strategic deployment to build world top-class mining company with the highest growth potential,Chinalco was now concentrating all efforts on making strategic transition and structural adjustment,strategic cooperation with the local governments where     

Jiangxi Promotes Jiangxi Copper Corporation To Become The World's Most Competitive Mining Company

<正>According to the latest info from Jiangxi Province State-owned Assets Supervision and Administration Commission,Jiangxi Copper Corporation was approved to become the first pilot enterprise for deepening reform.Contents of the pilot work is"Three Self"(self expansion,self decision-making,self     

Journal of Rare Earths Contents List of Vol.32(2014)

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Contributions to Baosteel Technical Research wanted

正Baosteel Technical Research,a quarterly journal,which is issued domestically and abroad,is run and sponsored by Baosteel Group Corporation.Baosteel Technical Research mainly reports the achievements in technological innovation,academic research,new product development and industrial equipment improvement by Baosteel.It will continue to follow up on hot topics and serve the company’s technological development and progress.Its readers include experts in     

Ministry of Industry and Information Technology: No Short Term Solution For Our Country’s Excess Nonferrous Metal Smelting Capacity

【正】According to the Ministry of Industry and Information Technology,the Ministry has released the 2013 Operation Report on China’s Industrial Communication Indu...     

Chinalco Signed Framework Agreement for Strategic Cooperation with Gansu Province

正Recently,Chinalco and Gansu Provincial People’s Government signed"Framework Agreement for Strategic Cooperation on Reform,Restructuring and Transition Development of Chinalco’s Electrolytic Aluminum Enterprises in Gansu",signifying that the strategic cooperation between Chinalco and Gansu Province had made new substantive progress.     

Unavoidable Economic Cycle:30% Of Nonferrous Metal Companies Were Involved In Restructuring

正Owing to continual downturn in real estate and bulk commodity markets,a number of traditional industries in China suffered unfavorable impact in performance.With the progressive disclosure of third quarter report,the no-pleasant-surprise performance of     

Baotou Rare Earth Became the World's Biggest High Performance Magnetic Material Base

正The High Performance Magnetic Material Phase II Project,an industry upgrading project implemented by Inner Mongolia Baotou IronSteel Rare Earth(Group)Hi-tech Co.,Ltd,recently basically finished equipment commissioning,signifying that the enterprise had developed the production capacity of15000 t/a Nd-Fe-B strip casting alloy and 5000t/a Nd-Fe-B magnet,thus becoming the world’s     

Introducing Two Central Enterprises to Integrate Rare Earth Industry,Shandong Rare Earth Group Breaks Surface

正With the signing of"Letter of intention for Propelling Integration of Shandong Rare Earth Enterprises"between Shandong Province Commission Of Economy and Informatization,China IronSteel Research Institute Group("China Steel Institute"),and China Rare MetalsRare Earth Co.,Ltd("China Rare Earth"),the"Shandong Rare Earth Group"jointly set up by the 3 units thus broke surface.On August 9,reporters of the China Economic Herald learned from Shandong Province     

Aluminium Production by Province or City in 2014

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