超塑成形理论与实践——王仲仁教授在超塑性研究领域的贡献

回顾了王仲仁教授在超塑性研究领域的一系列重要研究成果。Sn-Pb共晶超塑性材料薄壁管复合加载实验表明,在复杂应力状态下超塑材料遵守Mises屈服准则,并与Tresca屈服准则也接近,给出了超塑材料在应变速率强化条件下的屈服轨迹;研究了超塑变形过程中晶粒和孔洞的长大规律及其对变形中流动应力的影响,导出了包含晶粒长大和孔洞长大影响的超塑性本构关系;提出了测定超塑材料摩擦系数的理论校准曲线和应变速率敏感性指数的变截面拉伸试验法;开发了带有动凸模的微机控制的1000kN超塑成形机,研制了当时国内最大的微机控制的5000kN超塑成形机;在模具型腔超塑成形研究方面,成功挤压了130型汽车连杆锻模,是迄今为止尺寸最大的超塑成形模具钢型腔。

Theory and practice in the field of superplastic forming--Contribution of Professor Z.R.Wang in the research field of superplasticity

A series of important research achievements made by Professor Z. R. Wang in the research field of superplasticity are reviewed. Composite loading experiment of the thin wall tube made of Sn-Pb eutectic superplastic material shown that, superplastic material abides by Mises yield criteria and is close to Tresca yield criteria under complex stress condition. The Yield track of superplastic material under the condition of the strain rate strengthening was given. The growing laws of grains and holes and their influences to the flow stress during the superplastic deformation process were studied. Constitutive relation considering the effect of grains and holes' growing was deduced. A theory calibration curve to measure the fraction coefficient of superplastic material and a variable cross-section tensile test method to measure the strain-rate sensitivity coefficient were put forward. A lOOOkN superplastic forming machine controlled by computer with movable male punch and a SOOOkN superplastic forming machine controlled by computer, the biggest one on the time, were developed. In the research field of superplastic forming in the cavity die, a forging die to produce type 130 automobile's connecting rod, which is the biggest die steel cavity of superplastic forming until now, was extruded successfully.