News

Mitsubishi Materials Corporation ("MMC") has developed "MZC®1" SH+, a new chromium zirconium-based copper (Cu-Cr-Zr) alloy product that boasts both a high level of mechanical strength and electrical conductivity.

In line with the growth of next-generation vehicles such as xEVs in recent years, demand has increased for automotive electronic and electrical equipment for high voltage and high current applications. In response to this demand, MMC has leveraged its proprietary advanced processing and heat treatment technologies to supply "MZC®1," a highly conductive and heat-resistant chromium zirconium-based copper alloy, as a material for relays, terminals and connectors for high-voltage and high-current applications, and this new alloy is garnering high acclaim. Meanwhile, we anticipate higher demand for metal materials that can function under more severe conditions for next-generation automotive parts, which are expected to continue to evolve significantly in the future.
MMC has recently succeeded in developing "MZC®1 SH+," which achieves a higher level of strength and electrical conductivity than the existing "MZC®1" series. "MZC®1 SH+" will offer greater flexibility in part design as a material indispensable for next-generation automotive parts such as connectors and relays used to connect circuit boards that will require higher performance in the future.

Specific features of "MZC®1 SH+" are as follows.

1. High strength and high electrical conductivity
   "MZC®1 SH+" has the best balance of high mechanical strength and high electrical conductivity among all copper alloys. (tensile strength at approx. 670 MPa, electrical conductivity at 78% IACS)
   Compared to the temper designation (*1) H of the existing "MZC®1" series, tensile strength has been improved by approximately 70 MPa and to temper designation SH, tensile strength has been improved by approximately 40 MPa and electrical conductivity by approximately 4%. (Figure 1)
   

   (*1) Temper designation

   Classification of mechanical properties obtained by different processing and heat treatment methods in the manufacturing process.

   

   Figure 1: MZC®1 characteristic regions by temper designation
   (Click the picture to see the enlarged image)

2. Outstanding stress relaxation resistance (resilience of a spring) (*2) and fatigue characteristics (*3)
   As with the existing "MZC®1" series, this product features reduced stress relaxation during use at high temperatures and has extremely high reliability for use in conductive parts, even in high temperature environments of 150 to 200℃. (Figure 2) It also has fatigue characteristics equivalent or superior to those of the existing "MZC®1" series when subjected to repeated bending and offers extremely high reliability for use in conductive parts that require resistance to vibration. (Figure 3)
   
   

   

   Figure 2: MZC®1 SH+ stress relaxation resistance
   (Click the picture to see the enlarged image)

   

   Figure 3: MZC®1 SH+ fatigue characteristics
   (Click the picture to see the enlarged image)

   (*2) Stress relaxation resistance

   For a thin plate sample, the residual stress rate is evaluated as the spring force that remains after placing the sample in a high temperature environment for 1000 hours while subjecting it to a load within the elastic range where its spring properties are exhibited (80% load relative to 0.2% proof stress). The higher the residual stress rate, the better the stress relaxation resistance, meaning that it is less prone to spring fatigue and spring properties are sufficiently maintained even if used in a high temperature environment.

   (*3) Fatigue characteristics

   Repeated bending stress is applied to a thin plate sample to identify the number of repeated vibrations at break corresponding to the maximum bending stress applied and the results are plotted into a stress-number of cycles to failure diagram (S-N diagram).

MMC Group has established "For people, society and the earth, circulating resources for a sustainable future" as Our Commitment. We will continue to strive to realize Our Commitment through the supply of nonferrous metal materials and other highly functional materials and products.